Devices and methods for intracardiac procedures

ABSTRACT

The invention provides devices and methods for performing less-invasive surgical procedures within an organ or vessel. In an exemplary embodiment, the invention provides a method of closed-chest surgical intervention within an internal cavity of a patient&#39;s heart or great vessel. According to the method, the patient&#39;s heart is arrested and cardiopulmonary bypass is established. A scope extending through a percutaneous intercostal penetration in the patient&#39;s chest is used to view an internal portion of the patient&#39;s chest. An internal penetration is formed in a wall of the heart or great vessel using cutting means introduced through a percutaneous penetration in an intercostal space in the patient&#39;s chest. An interventional tool is then introduced, usually through a cannula positioned in a percutaneous intercostal penetration. The interventional tool is inserted through the internal penetration in the heart or great vessel to perform a surgical procedure within the internal cavity under visualization by means of the scope. In a preferred embodiment, a cutting tool is introduced into the patient&#39;s left atrium from a right portion of the patient&#39;s chest to remove the patient&#39;s mitral valve. A replacement valve is then introduced through an intercostal space in the right portion of the chest and through the internal penetration in the heart, and the replacement valve is attached in the mitral valve position.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of commonly-assigned,co-pending application Ser. No. 08/163,241, filed Dec. 6, 1993, which isa continuation-in-part of application Ser. No. 08/023,778, filed Feb.22, 1993. This application is also a continuation-in-part of copendingapplication Ser. No. 08/159,815, filed Nov. 30, 1993, which is a U.S.counterpart of Australian Patent Application No. PL 6170, filed Dec. 3,1992. The complete disclosures of all of these applications are herebyincorporated herein by reference.

FIELD OF THE INVENTION

[0002] This invention relates generally to instruments and techniquesfor performing less-invasive surgical procedures, and more specifically,to instruments and techniques for less-invasive surgery within the heartand great vessels.

BACKGROUND OF THE INVENTION

[0003] Various types of surgical procedures are currently performed toinvestigate, diagnose, and treat diseases of the heart and the greatvessels of the thorax. Such procedures include repair and replacement ofmitral, aortic, and other heart valves, repair of atrial and ventricularseptal defects, pulmonary thrombectomy, treatment of aneurysms,electrophysiological mapping and ablation of the myocardium, and otherprocedures in which interventional devices are introduced into theinterior of the heart or a great vessel.

[0004] Using current techniques, many of these procedures require agross thoracotomy, usually in the form of a median sternotomy, to gainaccess into the patient's thoracic cavity. A saw or other cuttinginstrument is used to cut the sternum longitudinally, allowing twoopposing halves of the anterior or ventral portion of the rib cage to bespread apart. A large opening into the thoracic cavity is thus created,through which the surgical team may directly visualize and operate uponthe heart and other thoracic contents.

[0005] Surgical intervention within the heart generally requiresisolation of the heart and coronary blood vessels from the remainder ofthe arterial system, and arrest of cardiac function. Usually, the heartis isolated from the arterial system by introducing an external aorticcross-clamp through a sternotomy and applying it to the aorta betweenthe brachiocephalic artery and the coronary ostia. Cardioplegic fluid isthen injected into the coronary arteries, either directly into thecoronary ostia or through a puncture in the aortic root, so as to arrestcardiac function. In some cases, cardioplegic fluid is injected into thecoronary sinus for retrograde perfusion of the myocardium. The patientis placed on cardiopulmonary bypass to maintain peripheral circulationof oxygenated blood.

[0006] Of particular interest to the present invention are intracardiacprocedures for surgical treatment of heart valves, especially the mitraland aortic valves. According to recent estimates, more than 79,000patients are diagnosed with aortic and mitral valve disease in U.S.hospitals each year. More than 49,000 mitral valve or aortic valvereplacement procedures are performed annually in the U.S., along with asignificant number of heart valve repair procedures.

[0007] Various surgical techniques may be used to repair a diseased ordamaged valve, including annuloplasty (contracting the valve annulus),quadrangular resection (narrowing the valve leaflets), commissurotomy(cutting the valve commissures to separate the valve leaflets),shortening mitral or tricuspid valve chordae tendonae, reattachment ofsevered mitral or tricuspid valve chordae tendonae or papillary muscletissue, and decalcification of valve and annulus tissue. Alternatively,the valve may be replaced, by excising the valve leaflets of the naturalvalve, and securing a replacement valve in the valve position, usuallyby suturing the replacement valve to the natural valve annulus. Varioustypes of replacement valves are in current use, including mechanical andbiological prostheses, homografts, and allografts, as described inBodnar and Frater, Replacement Cardiac Valves 1-357 (1991), which isincorporated herein by reference. A comprehensive discussion of heartvalve diseases and the surgical treatment thereof is found in Kirklinand Barratt-Boyes, Cardiac Stragey 323-459 (1986), the completedisclosure of which is incorporated herein by reference.

[0008] The mitral valve, located between the left atrium and leftventricle of the heart, is most easily reached through the wall of theleft atrium, which normally resides on the posterior side of the heart,opposite the side of the heart that is exposed by a median sternotomy.Therefore, to access the mitral valve via a sternotomy, the heart isrotated to bring the left atrium into an anterior position accessiblethrough the sternotomy. An opening, or atriotomy, is then made in theright side of the left atrium, anterior to the right pulmonary veins.The atriotomy is retracted by means of sutures or a retraction device,exposing the mitral valve directly posterior to the atriotomy. One ofthe forementioned techniques may then be used to repair or replace thevalve.

[0009] An alternative technique for mitral valve access may be used whena median sternotomy and/or rotational manipulation of the heart areundesirable. In this technique, a large incision is made in the rightlateral side of the chest, usually in the region of the fifthintercostal space. One or more ribs may be removed from the patient, andother ribs near the incision are retracted outward to create a largeopening into the thoracic cavity. The left atrium is then exposed on theposterior side of the heart, and an atriotomy is formed in the wall ofthe left atrium, through which the mitral valve may be accessed forrepair or replacement.

[0010] Using such open-chest techniques, the large opening provided by amedian sternotomy or right thoracotomy enables the surgeon to see themitral valve directly through the left atriotomy, and to position his orher hands within the thoracic cavity in close proximity to the exteriorof the heart for manipulation of surgical instruments, removal ofexcised tissue, and/or introduction of a replacement valve through theatriotomy for attachment within the heart. However, these invasive,open-chest procedures produce a high degree of trauma, a significantrisk of complications, an extended hospital stay, and a painful recoveryperiod for the patient. Moreover, while heart valve surgery producesbeneficial results for many patients, numerous others who might benefitfrom such surgery are unable or unwilling to undergo the trauma andrisks of current techniques.

[0011] What is needed, therefore, are devices and methods for carryingout heart valve repair and replacement as well as other procedureswithin the heart and great vessels that reduce the trauma, risks,recovery time and pain that accompany current techniques. The devicesand methods should facilitate surgical intervention within the heart orgreat vessels without the need for a gross thoracotomy, preferablythrough small incisions within intercostal spaces of the rib cage,without cutting, removing, or significantly deflecting the patient'sribs or sternum. In particular, the devices and methods should allow forremoval of tissue from the thoracic cavity, as well as for introductionof surgical instruments, visualization devices, replacement valves andthe like into the thoracic cavity, to facilitate heart valve repair andreplacement. Preferably, the devices and methods should facilitatereplacement of a heart valve with various types of prostheses, includingmechanical and biological prostheses, homografts, and allografts.

SUMMARY OF THE INVENTION

[0012] The invention provides devices and methods for performingless-invasive surgical procedures within an organ or vessel, andparticularly, within the heart and great vessels of the thoracic cavity.The devices and methods of the invention facilitate intervention withinthe heart or great vessels without the need for a median sternotomy orother form of gross thoracotomy, substantially reducing trauma, risk ofcomplication, recovery time, and pain for the patient. Using the devicesand methods of the invention, surgical procedures may be performedthrough percutaneous penetrations within intercostal spaces of thepatient's rib cage, without cutting, removing, or significantlydisplacing any of the patient's ribs or sternum. The devices methods arcparticularly well-adapted for heart valve repair and replacement,facilitating visualization within the patient's thoracic cavity, repairor removal of the patient's natural valve, and, if necessary, attachmentof a replacement valve in the natural valve position. The inventionfacilitates valve replacement with any of a variety ofcommercially-available replacement valves, including mechanicalprostheses, bioprostheses, homografts, and allografts.

[0013] In a first preferred embodiment, the invention provides a methodof closed-chest surgical intervention within an internal cavity of thepatient's heart or great vessel. Utilizing the method of the invention,the patient's heart is arrested and cardiopulmonary bypass isestablished. An internal portion of the patient's chest is viewed bymeans of a scope extending through a percutaneous intercostalpenetration in the patient's chest. A cutting means is introducedthrough a percutaneous intercostal penetration in the patient's chest,and the cutting means is used to form an internal penetration in a wallof the heart or great vessel. An interventional tool is then introducedthrough a percutaneous intercostal penetration and through the internalpenetration in the heart or great vessel to perform a surgical procedurewithin the internal cavity under visualization by means of the scope.One or more percutaneous cannulae may be positioned within anintercostal space of the chest wall through which the interventionaltool may be introduced into the chest cavity. The surgical procedureswhich may be performed within the heart or great vessel include repairor replacement of heart valves, repair of atrial and ventricular septaldefects, pulmonary thrombectomy, treatment of aneurysms,electrophysiological mapping and ablation of the myocardium, myocardialdrilling, correction of congenital defects, coronary artery bypassgrafting, and other procedures.

[0014] The patient's heart is preferably arrested by occluding thepatient's aorta between the patient's coronary arteries and thepatient's brachiocephalic artery with an expandable member on a distalend of an endovascular catheter. Cardioplegic fluid is then introducedthrough a lumen in the catheter into the patient's aorta upstream of theexpandable member to arrest cardiac function. Alternatively, or inaddition to such antegrade cardioplegic fluid delivery, cardioplegicfluid may be delivered in a retrograde manner by means of a catheterpositioned in the coronary sinus of the patient's heart. In analternative approach, an external cross-clamp may be placedthoracoscopically on the aorta through a small incision or cannula inthe patient's chest. Cardioplegic fluid may be delivered through eithera thoracoscopically introduced cannula or an endovascular catheterextending into the ascending aorta upstream of the cross-clamp.

[0015] In one aspect the present invention consists in a method forinducing cardioplegic arrest of a heart in situ in a patient's body,comprising the steps of:

[0016] (a) maintaining systemic circulation with peripheralcardiopulmonary by-pass;

[0017] (b) occluding the ascending aorta through a percutaneously placedarterial balloon catheter;

[0018] (c) introducing a cardioplegic agent into the coronarycirculation; and

[0019] (d) venting the left side of the heart.

[0020] The method according to the present invention may be carried outon humans or other mammalian animals. The method is of particularapplicability in humans as it allows an alternative approach to openheart surgery and the development of closed cardioscopic surgery. Themethod according to the invention enables a percutaneous by-pass systemto be associated with cardioplegia, venting and cooling of the heartwhich subverts the need for median sternotomy. This may, in turn, reducethe complications of the surgery.

[0021] The maintenance of the systemic circulation involves establishinga cardiopulmonary by-pass. The blood may be drawn into the by-passmerely by positioning a percutaneous catheter into the right atriumand/or into one or both of the vena cavae through which venous blood maybe drawn from the heart into an extracorporeal pump oxygenator. In morepreferred embodiments of the invention a single catheter with twoinflatable cuffs, or two separate catheters, each with an inflatablecuff are introduced into the vena cavae to occlude them adjacent totheir right atrial inlets. This allows isolation of the right atrium andallows blood to be drawn from the vena cavae into the by-pass system.There is also preferably provision for percutaneous communication viaone catheter with the right atrium to allow infusion of saline into theright atrium. This infusion has the advantage that it allows the heartto be cooled and improves visual acuity within the right heart allowingdirect cardioscopic examination and/or intervention.

[0022] The catheter used to decompress the right atrium and to drawblood into the by-pass is preferably introduced through the femoral veinby percutaneous puncture or direct cut down. If other than simple venousdrainage is required catheters with inflatable cuffs, as describedabove, are placed preferably such that in inflatable cuff of the cannulais positioned within each of the inferior (suprahepatic) and superiorvena cavae. There is preferably a lumen in the cannula acting as acommon blood outlet from the vena cavae leading to the pump oxygenator.A separate lumen is preferably used to infuse saline between the twoinflated cuffs into the right atrium. If, alternatively, separatecatheters are used to occlude each of the inferior and superior venacavae than the cannula for the inferior vena cavae is preferablyintroduced percutaneously from the femoral vein and that for thesuperior vena cavae is introduced percutaneously through the jugular orsubclavian vein.

[0023] The ascending aorta is preferably occluded by a balloon catheterintroduced percutaneously through the femoral artery. This catheter mustcarry adjacent its tip an inflatable cuff or balloon of sufficient sizethat upon being inflated it is able to completely occlude the ascendingaorta. The length of the balloon should preferably not be so long as toimpede the flow of blood or other solution to the coronary arteries orto the brachiocephalic, left carotid or left subclavian arteries. Aballoon length of about 40 mm and diameter of about 35 mm is suitable inhumans. The balloon is of a cylindrical shape to fully and evenlyaccommodate the lumen of the ascending aorta. This maximizes the surfacearea contact with the aorta, and allows for even distribution ofocclusive pressure.

[0024] The balloon of the catheter is preferably inflated with a salinesolution to avoid the possibility of introducing into the patient an airembolism in the event that the balloon ruptured. The balloon should beinflated to a pressure sufficient to prevent regurgitation of blood intothe aortic root and to prevent migration of the balloon into the rootwhilst not being so high as to cause damage or dilation to the aorticwall. An intermediate pressure of the order of 350 mmHg has been proveneffective in trials.

[0025] The aortic catheter is preferably introduced under fluoroscopicguidance over a suitable guidewire. Transoesophageal echocardiographycan alternatively be used for positioning as has been described withreference to the venous catheter. The catheter may serve a number ofseparate functions and the number of lumina in the catheter will dependupon how many of those functions the catheter is to serve. The cathetercan be used to introduce the cardioplegic agent, normally in solution,into the aortic root via one lumen. The luminal diameter will preferablybe such that a flow of the order of 250-500 ml/in of cardioplegicsolution can be introduced into the aortic root under positive pressureto perfuse adequately the heart by way of the coronary arteries. Thesame lumen can, by applying negative pressure to the lumen from anoutside source, effectively vent the left heart of blood or othersolutions. It may also be desirable to introduce medical instrumentsand/or a cardioscope into the heart through another lumen in thecatheter. The lumen should be of a diameter suitable to pass afibre-optic light camera of no greater than 3 mm diameter. It ishowever, preferable that the diameter and cross-sectional design of theinternal lumina is such that the external diameter of the catheter inits entirety is small enough to allow its introduction into the adultfemoral artery by either percutaneous puncture or direct cut-down

[0026] The oxygenated blood returning to the body from the by-passsystem may be conveyed into the aorta from another lumen in the cannulacarrying the balloon. In this case the returning blood is preferablydiscarded from the catheter in the external iliac artery. In anotherembodiment of the invention, and in order to reduce the diameter of thecatheter carrying the balloon, a separate arterial catheter of knowntype may be used to return blood to the patient from the by-pass system.In this case a short catheter is positioned in the other femoral arteryto provide systemic arterial blood from the bypass system. The controlend of the catheter, i.e. that end that remains outside of the body,should have separate ports of attachment for the lumina. The catheterlength should be approximately 900 mm for use in humans.

[0027] The cardioplegic agent may be any of the known materialspreviously known to be useful, or in the future found to be useful, ascardioplegic agents. The agent is preferably infused as a solution intothe aortic root through one of the lumina of the aortic catheter.

[0028] In another aspect the present invention consists in a catheterfor use in occluding the ascending aorta comprising an elongate tubehaving one or more continuous lumina along its length, an inflatablecuff is disposed about the tube adjacent one end thereof, the cuff beingof such a size that upon being inflated it is able to occlude theascending aorta of a patient.

[0029] The invention thus contemplates, at least in its preferredembodiments, the possibility of effective ascending aortic occlusion,cardioplegia, venting, right heart deflation and topical cooling inassociation with extracorporeal cardiopulmonary by-pass all withoutnecessitating a median sternotomy or other thoracic incision.

[0030] The catheter and method used to induce cardioplegic arrest may beused in a number of surgical procedures. These include the following:

[0031] (1) Coronary artery revascularization such as:

[0032] (a) angioscopic laser introduction or angioscopic balloonangioplasty catheter into the coronary arteries via one lumen of theaortic catheter; or

[0033] (b) thoracoscopic dissection of one or both of the mammaryarteries with revascularization achieved by distal anastomoses of theinternal mammary arteries to coronary arteries via a small left anteriorthoracotomy.

[0034] (2) Secundum-type atrial septal defect repair such as by:

[0035] (a) “Closed” cardioscopic closure, or

[0036] (b) Closure as an “open” procedure via a mini-right thoracotomy.

[0037] (3) Sinus venosus defect repairs similar to 2 above.

[0038] (4) Infundibular stenosis relief by cardioscopic techniques.

[0039] (5) Pulmonary valvular stenosis relief by cardioscopictechniques.

[0040] (6) Mitral valve surgery via a small right thoracotomy.

[0041] (7) Aortic stenosis relief by the introduction of instrumentationvia a lumen in the aortic catheter into the aortic root.

[0042] (8) Left ventricular aneurysm repair via a small left anteriorthoracotomy.

[0043] In a preferred embodiment, the surgical procedure comprisessurgically treating a heart valve. Such surgical treatment may involverepairing the valve by introducing instruments through an intercostalpenetration and through the internal penetration in the heart toperform, for example, annuloplasty, quadrangular resection of valveleaflets, commissurotomy, reattachment of chordae tendonae or papillarymuscle tissue, shortening of chordae tendonae, decalcification, and thelike.

[0044] The heart valve may also be replaced with a replacement valve. Inthis embodiment, the method may further comprise the step of removingall or part of the patient's natural heart valve by means of a cuttingtool introduced through a percutaneous intercostal penetration andthrough the internal penetration in the heart. The method furthercomprises the step of introducing a replacement valve through apercutaneous intercostal penetration and through the internalpenetration into the internal cavity within the heart. The replacementvalve is then fastened within the heart, usually by means of aninstrument introduced through a percutaneous intercostal penetration andthrough the internal penetration in the heart wall.

[0045] The method may further include the step of sizing the patient'sheart valve before the replacement valve is introduced. In an exemplaryembodiment, a sizing instrument is introduced through a percutaneousintercostal penetration and through the internal penetration in theheart to measure the size of the valve annulus and to determine the sizeof the replacement valve.

[0046] The replacement valve may be fastened in position in variousways, including suturing the replacement valve to an annulus at thenatural valve position in the heart. In one embodiment, the sutures areapplied to the annulus at the valve position, drawn out of the patient'sbody through the internal penetration and through a percutaneousintercostal penetration, and then applied to the replacement valve. Thesutures may further be radially arranged in spaced-apart locations aboutan organizer ring disposed outside of the patient's body. The suturesare then held in tension as the replacement valve is introduced into theinterior of the heart and positioned in the natural valve position. Thereplacement valve may be introduced by means of a valve holder attachedto an elongated handle, or simply pushed along the sutures by means ofthe surgeon's hands or conventional tools such as forceps or needledrivers.

[0047] In a particular preferred embodiment, the heart valve comprises amitral valve which is disposed between the left atrium and leftventricle of the patient's heart. A percutaneous penetration is madewithin an intercostal space in a right lateral portion of the patient'schest, usually within the fourth, fifth, or sixth intercostal space.From this penetration, an internal penetration may be formed in the wallof the left atrium at a location which is in a generally straight linedrawn from the penetration in the right lateral portion of the chest tothe patient's mitral valve. In this way, surgical instruments may beintroduced from the penetration in the right chest to form the internalpenetration in the heart wall, repair or excise the patient's naturalvalve, and introduce and attach a replacement valve.

[0048] In a further aspect of the invention, a prosthesis assembly isprovided for closed-chest replacement of a heart valve. The prosthesisassembly comprises a replacement valve having an annular attachmentportion and a movable valve portion coupled to the attachment portion.The prosthesis assembly further includes holder means releasably mountedto the attachment portion, wherein the holder means is configured toallow introduction of the replacement valve through an intercostal spacein the patient's chest.

[0049] In a preferred embodiment, the replacement valve and the holdermeans together have a profile with a width which is less than the widthof the intercostal space. Preferably, the intercostal space is less thanabout 20 mm in width. The attachment portion of the replacement valvewill usually have an outer diameter which is greater than theintercostal width.

[0050] The holder means of the device preferably comprises an elongatedhandle having a distal end mounted to the replacement valve and aproximal end opposite the distal end. The handle is configured tointroduce the replacement valve into the patient's heart through theintercostal space. Preferably, the handle is at least about 20 cm inlength to allow positioning the replacement valve in the heart from aright lateral portion of the patient's chest. The handle may furtherinclude means for releasing the replacement valve, the releasing meansbeing configured for actuation from the proximal end of the handle.

[0051] The handle may also include means for pivoting the replacementvalve from a first orientation for introduction through the intercostalspace to a second orientation for attachment in the patient's heart. Thepivoting means is configured for actuation from a proximal end of thehandle. In this way, the replacement valve may be introduced edge-firstthrough the intercostal space, then pivoted about an axis generallyperpendicular to the handle into an orientation suitable for attachmentwithin the patient's heart. Alternatively, the valve prosthesis may becollapsible or compressible to permit introduction through anintercostal space into the thoracic cavity.

[0052] Preferably, the replacement valve is premounted to the holdermeans and the two are sterilized and packaged together in a sterilepack. In this way, the pack may be opened in the sterile operating roomenvironment with the valve and holder ready for immediate surgical use.

[0053] In a further embodiment, the invention provides a thoracoscopicdevice for placement of a replacement valve in a valve position of apatient's heart. In a preferred embodiment, the thoracoscopic devicecomprises an elongated handle configured for positioning through anintercostal space in the patient's chest, as described above. The deviceincludes means at a distal end of the handle for releasably holding areplacement valve in an orientation for introduction through theintercostal space, and may further include means for pivoting thereplacement valve relative to the handle from a first orientation forintroduction through the intercostal space, to a second orientation forplacement in the valve position. The thoracoscopic device furtherincludes, in a preferred embodiment, means at the proximal end of thehandle for releasing the replacement valve from the holding means oncethe prosthesis has been positioned and secured within the heart.

[0054] In a further aspect of the invention, a percutaneous accesscannula is provided to facilitate closed-chest replacement of a heartvalve in a patient's heart. The access cannula comprises a cannula bodyconfigured for placement in an intercostal space in the patient's chest,the cannula having a distal end, a proximal end, and a lumen extendingtherebetween. The lumen is configured to allow passage of a replacementvalve therethrough. An obturator is positionable in the lumen tofacilitate introduction of the cannula body. The obturator has across-sectional width that is equal to or less than the width of theintercostal space, and a cross-sectional height that is greater than thecross-sectional width.

[0055] The replacement valve has an annular attachment portion with anouter diameter, and the obturator as well as the lumen in the cannulahave a cross-sectional height at least equal to the outer diameter,allowing the replacement valve to be introduced through the lumen of thecannula. In one embodiment, the cross-sectional height of the lumen inthe cannula is about two to six times the cross-sectional width. Thelumen and obturator may have a rectangular cross-section, ovalcross-section, or other shape. The cannula body may be rigid ordeformable, while the obturator is usually rigid to facilitateintroduction.

[0056] The access cannula may further be provided with suture retainingmeans on its proximal end configured to retain a plurality of sutures ina spaced-apart relationship. The suture retaining means may have variousconfigurations, such as a plurality of slots in a proximal end of thecannula body in circumferentially spaced positions around the lumen. Theslots in the access cannula may further include means such as slitted,elastomeric inserts, for frictionally engaging the sutures to maintaintension thereon while the prosthesis is introduced into the heart.

[0057] A second organizing ring may also be provided in a positionspaced-apart from the access cannula outside of the patient's body. Thesecond organizing ring has an interior passage through which the suturesmay extend and a plurality of means circumferentially spaced around thepassage for frictionally engaging the sutures. In this way, sutures maybe applied to the valve annulus in the patient's heart, drawn throughthe lumen in the cannula and retained in the suture organizing means onthe access cannula's proximal end. The sutures may then be applied tothe replacement valve and retained in the second organizing ring. Onceall of the sutures have been applied to the prosthesis, the prosthesismay be introduced into the heart by sliding it along the sutures, whichare held in tension by the second organizing ring. Alternatively, thesutures may be held in tension by individual clamps, tape,commercially-available suture organizers, or other means for exertingtraction on the free ends of each individual suture.

[0058] The invention further provides a system for closed-chestreplacement of a heart valve in a patient's heart. The system includesmeans for forming a percutaneous intercostal penetration in thepatient's chest, and a visualization scope configured to pass through anintercostal space in the patient's chest for viewing an internal chestcavity. Means are also provided for arresting the patient's heart from alocation outside of the chest cavity. A cardiopulmonary bypass system,including means for delivering oxygenated blood to the patient'sarterial system, is provided for maintaining peripheral circulation ofoxygenated blood. Cutting means positionable through a percutaneousintercostal penetration into the chest cavity are provided for formingan internal penetration in a wall of the patient's heart or greatvessel. The system further provides interventional means positionablethrough a percutaneous intercostal penetration and through the internalpenetration for performing a surgical procedure within the heart orgreat vessel.

[0059] In a preferred embodiment, the means for arresting the heartcomprises an endovascular catheter having expandable means near itsdistal end for occluding the patient's ascending aorta between thepatient's coronary arteries and the patient's brachiocephalic artery.The catheter further includes an internal lumen for deliveringcardioplegic fluid into the aorta upstream of the expandable means toperfuse the myocardium through the coronary arteries.

[0060] The interventional means preferably comprises means for securinga replacement valve in a valve position within the patient's heart.Usually, the replacement valve securing means comprises an elongatedhandle like that described above, having means at its distal end forreleasably holding a replacement valve. The handle may also facilitatepivoting the replacement valve for introduction through an intercostalspace.

[0061] Preferably, the system also includes at least one cannulapositionable in a percutaneous intercostal penetration, through whichsurgical instruments or a replacement valve may be introduced into thethoracic cavity. The cannula may have a lumen with a cross-sectionalheight greater than its width to allow edge-first introduction of areplacement valve that has an outer diameter larger than the intercostalspace, as described above.

[0062] The system may further include cutting means positionable througha percutaneous intercostal penetration and through the internalpenetration in the patient's heart for removing at least a portion ofthe patient's heart valve. The cutting means for removing the heartvalve may comprise scissors, retractable knife, biters, or the like.

[0063] The system preferably includes means positionable through apercutaneous intercostal penetration and through the internalpenetration for sizing an annulus of the patient's heart valve. In oneembodiment, the sizing means comprises an elongated shaft and aplurality of interchangeable sizing disks of various sizes attachable toa distal end of the shaft. The shaft and sizing disk may be introducedthrough a percutaneous intercostal penetration and through the internalpenetration to position the sizing disk adjacent to the annulus of thepatient's heart valve, allowing a comparison of the annulus diameter tothe disk diameter. The sizing disk may be pivotable relative to theshaft to allow introduction into the thoracic cavity through anintercostal space. Alternative means for sizing may also be used, suchas expandable baskets, balloons, endoscopic or endovascularvisualization, fluoroscopy, or transesophageal echocardiography.

[0064] The system may further include means for attaching thereplacement valve to the patient's heart, which comprises, in oneembodiment, means for suturing the replacement valve to a valve annulusin the patient's heart. The system preferably includes organizing meansfor maintaining the sutures in spaced-apart positions outside of thechest cavity after the sutures have been applied to the valve annuluswithin the heart. The organizing means is preferably fixed to a proximalend of a cannula disposed in a percutaneous intercostal penetration, asdescribed above. In this way, the sutures may be applied to the naturalvalve annulus within the patient's heart, drawn out of the chest cavitythrough the cannula lumen, and positioned in spaced-apart positionsabout the circumference of the proximal end of the cannula. Means mayalso be provided for maintaining tension on the ends of the suturesafter they have been applied to the replacement valve. This facilitatesadvancing the replacement valve along the sutures, through the lumen inthe cannula, and into the chest cavity.

[0065] The system may further include retraction means positionablethrough an intercostal space in the patient's chest for opening theinternal penetration in the wall of the heart or great vessel. Theretraction means may comprise a collapsible rake, tethered clamp,retraction sutures, or the like.

[0066] A further understanding of the nature and advantages of theinvention may be realized by reference to the remaining portions of thespecification and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0067]FIG. 1 is a perspective view of a system for closed-chest mitralvalve replacement constructed in accordance with the principles of thepresent invention, showing the use of the system in a patient.

[0068]FIG. 2 is a front view of the system of FIG. 1, showing thepositioning of the system in the patient's chest.

[0069]FIG. 3 is a front view of a patient's cardiovascular systemillustrating the positioning of a system for arresting the heart andestablishing cardiopulmonary bypass in accordance with the principles ofthe present invention.

[0070]FIG. 4 is a top view looking into the patient's thoracic cavitythrough a passage of an access cannula in the system of FIG. 1. showingthe creation of an atriotomy in the patient's left atrium.

[0071]FIG. 5 is a top view looking into the patient's thoracic cavitythrough a passage of an access cannula in the system of FIG. 1, showingthe removal of the mitral valve leaflets.

[0072]FIG. 6 is a top view looking into the patient's thoracic cavitythrough a passage of an access cannula in the system of FIG. 1, showingthe application of sutures to the mitral valve annulus.

[0073]FIG. 7 is a perspective view of the system of FIG. 1 positioned inthe patient, showing the application of sutures to a replacement valve.

[0074] FIGS. 8A-8B are transverse cross-sectional views of the systemand patient of FIG. 1 taken through the patient's thorax, showing theintroduction of the replacement valve into the left atrium and the tyingof knots in the sutures to secure the prosthesis in the patient's heart.

[0075]FIG. 9 is a top view looking into the patient's thoracic cavitythrough a passage of an access cannula in the system of FIG. 1, showingpushing the knots toward the replacement valve and trimming the freeends of the sutures.

[0076]FIG. 10 is a top view looking into the patient's thoracic cavitythrough a passage of an access cannula in the system of FIG. 1, showingthe closure of the patient's left atrium.

[0077] FIGS. 11A-11C are perspective, front, and top views respectivelyof the access cannula in the system of FIG. 1.

[0078]FIG. 11D is a partial cut-away view taken along line 11D-11D inFIG. 11C.

[0079]FIG. 12A is a side view of angled scissors in the system of FIG.1.

[0080] FIGS. 12B-12D are side views of a distal portion of the scissorsof FIG. 12A showing alternative embodiments thereof.

[0081]FIG. 13 is a side view of a retractable knife in the system ofFIG. 1.

[0082] FIGS. 14A-14B are side and top views, respectively, of graspingforceps in the system of FIG. 1.

[0083]FIG. 15 is a perspective view of a left atrial retractor in thesystem of FIG. 1.

[0084] FIGS. 16A-16B are side and top views, respectively, of needledrivers in the system of FIG. 1.

[0085] FIGS. 17A-17B are top and side views, respectively, of areplacement valve in the system of FIG. 1.

[0086]FIG. 17C is an end view of the replacement valve of FIGS. 17A-17Bpositioned in a passage of an access cannula in the system of FIG. 1.

[0087]FIG. 18 is a perspective view of a prosthesis introducer in thesystem of FIG. 1.

[0088]FIG. 19A is a side view of the prosthesis introducer of FIG. 18.

[0089] FIGS. 19B-19C are bottom and side views, respectively, of adistal portion of the prosthesis introducer of FIG. 18.

[0090] FIGS. 19D-19E are top and side views, respectively, of astationary arm of the prosthesis introducer of FIG. 18.

[0091] FIGS. 19F-19G are top and side views, respectively, of a movablearm of the prosthesis introducer of FIG. 18.

[0092]FIG. 20A is a side partial cut-away view of the prosthesisintroducer of FIG. 18.

[0093]FIG. 20B is a top partial cut-away view of a distal portion of theprosthesis introducer of FIG. 18.

[0094]FIG. 21 is a perspective view of a sizing disk in the system ofFIG. 1, positioned on the introducer of FIG. 18.

[0095]FIGS. 22, 23A and 23B are top and side views, respectively, of thesizing disk of FIG. 21.

[0096] FIGS. 23A-23B are top and side views, respectively, of the sizingdisk of FIG. 21.

[0097] FIGS. 24A-24C are front, top, and side views, respectively of asuture organizing ring in the system of FIG. 1.

[0098] FIGS. 25A-25B are side and top views, respectively of aknot-pushing device in the system of FIG. 1.

[0099]FIG. 26 is a schematic partly cut-away representation of apatient's heart having percutaneous catheters placed therein forcarrying out the method according to the present invention;

[0100]FIG. 27 is a similar view to FIG. 26 showing the aortic catheterin position but including an angioscope and a left ventricular ventingcannula introduced into the aortic root and left ventricle respectively,via separate lumina within the aortic catheter;

[0101]FIG. 28 is a front elevational view of part of the vascular systemof a patient showing, inter alia, the aortic balloon catheter positionedin the ascending aorta via the femoral artery;

[0102]FIG. 29 is a side elevational view of the control end of theaortic catheter according to the present invention;

[0103]FIG. 30 is a partly cut away side elevational view of the balloonend of the catheter of FIG. 29 in an inflated condition;

[0104]FIG. 31a is a cross-sectional view of the catheter of FIG. 29intermediate the control end and the balloon end;

[0105]FIG. 31b is an alternative cross-sectional arrangement of thelumina in the catheter of FIG. 29;

[0106]FIG. 32 is a cross-sectional view through the balloon end of thecatheter of FIG. 29;

[0107]FIGS. 33a and 33 b show schematically two alternative arrangementsto the catheter shown in FIG. 29;

[0108]FIGS. 34a and 34 b show schematically two alternative catheterarrangements for the isolation of the right atrium and venous drainage.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0109] The invention provides methods and devices for performingsurgical interventions within the heart or a great vessel such as theaorta, superior vena cava, inferior vena cava. pulmonary artery,pulmonary vein, coronary arteries, and coronary veins, among othervessels. While the specific embodiments of the invention describedherein will refer to mitral valve repair and replacement, it should beunderstood that the invention will be useful in performing a greatvariety of surgical procedures, including repair and replacement ofaortic, tricuspid, or pulmonary valves, repair of atrial and ventricularseptal defects, pulmonary thrombectomy, removal of atrial myxoma, patentforamen ovate closure, treatment of aneurysms, electrophysiologicalmapping and ablation of the myocardium, myocardial drilling, coronaryartery bypass grafting, angioplasty, atherectomy, correction ofcongenital defects, and other procedures in which interventional devicesare introduced into the interior of the heart, coronary arteries, orgreat vessels. Advantageously, the invention facilitates the performanceof such procedures through percutaneous penetrations within intercostalspaces of the rib cage, obviating the need for a median sternotomy orother form of gross thoracotomy.

[0110] The terms “percutaneous intercostal penetration” and “intercostalpenetration” as used herein refer to a penetration, in the form or asmall cut, incision, hole, cannula, trocar sleeve, or the like, throughthe chest wall between two adjacent ribs, wherein the patient's rib cageand sternum remain substantially intact, without cutting, removing, orsignificantly displacing the ribs or sternum. These terms are intendedto distinguish a gross thoracotomy such as a median sternotomy, whereinthe sternum and/or one or more ribs are cut or removed from the ribcage, or one or more ribs are retracted significantly, to create a largeopening into the thoracic cavity. A “percutaneous intercostalpenetration” may abut or overlap the adjacent ribs between which it isformed, but the maximum width of the penetration which is available forintroduction of instruments, prostheses and the like into the thoraciccavity will be the width of the intercostal space, bounded by twoadjacent ribs in their natural, substantially undeflected positions. Itshould be understood that one or more ribs may be retracted or deflecteda small amount without departing from the scope of the invention;however, the invention specifically seeks to avoid the pain, trauma, andcomplications which result from the large deflection or cutting of theribs in conventional, open-chest techniques.

[0111] A first preferred embodiment of a system and method ofclosed-chest mitral valve replacement according to the invention will bedescribed with reference to FIGS. 1-10. FIG. 1 illustrates a system 20for closed-chest valve replacement positioned in a patient P on anoperating table T. Preferably, a wedge or block W having a top surfaceangled at approximately 20° to 45° is positioned under the right side ofpatient P so that the right side of the patient's body is somewhathigher than the left side. The patient's right arm A is allowed torotate downward to rest on table T, exposing the right lateral side ofthe patient's chest.

[0112] The valve replacement system 20 includes an access cannula 22positioned percutaneously within an intercostal space between two ribs(shown in phantom) in a right lateral side of the patient's chest.Additional thoracoscopic trocar sleeves 24 of conventional constructionare positioned within intercostal spaces in the right lateral chestinferior and superior to access cannula 22, as well as in the rightanterior (or ventral) portion of the chest. An endoscope 25 ofconventional construction is positioned through a percutaneousintercostal penetration into the patient's chest, usually through one oftrocar sleeves 24. The distal end of endoscope 25 (shown in phantom) ispreferably configured to view at an angle between about 30° and 90°relative to the shaft of endoscope 25, to facilitate visualization ofthe heart from the right portion of the thoracic cavity. A light source(not shown) is also provided on endoscope 25 to illuminate the thoraciccavity. A video camera 26 is mounted to the proximal end of endoscope25, and is connected to a video monitor 28 for viewing the interior ofthe thoracic cavity. A first suture organizing ring 30 is mounted to aproximal end of access cannula 22. A second organizing ring 32 ismounted to a support stand 34 fixed to table T. A replacement valve 36is held at the distal end of an introducer 38 between first organizingring 30 and second organizing ring 32. Introducer 38 extends throughsecond organizing ring 32 and is supported by support stand 34.Additional instruments to be used in a procedure such as a retractor 40,as well as cutting, suturing, stapling, aspirating, irrigating and otherdevices, may be introduced through access cannula 22, trocar sleeves 24,and/or small, percutaneous incisions within intercostal spaces of therib cage.

[0113] Referring now to FIG. 2, access cannula 22 is positioned withinan intercostal space I in the right lateral side of the chest,preferably in the third, fourth, fifth, or sixth intercostal spacebetween adjacent ribs R. Additional trocar sleeves 24A, 24B arepositioned within intercostal spaces superior and inferior to accesscannula 22 in the right lateral side of the chest. Access cannula 22 andtrocar sleeves 24A, 24B are positioned so that instruments 42 introducedthrough them may be directed toward the right side of the left atrium ofthe heart H. A trocar sleeve 24C is positioned in an intercostal spacein the right anterior side of the chest such that endoscope 25 may beintroduced to view the thoracic cavity and heart H without interferingwith instruments introduced through access cannula 22 or trocar sleeves24A, 24B. An additional trocar sleeve 24D is positioned in anintercostal space in the anterior side of the chest just to the right ofthe sternum and anterior to the right lateral side of the heart H.

[0114] It will be understood to those of ordinary skill in the art that,in some cases. it may desirable to eliminate some or all of trocarsleeves 24 and/or access cannula 22, and introduce instruments directlythrough small, percutaneous intercostal incisions in the chest.Advantageously, unlike laparoscopic, arthroscopic, and other endoscopicprocedures, no distension of the chest is required using the method ofthe invention, so that leakage of distension fluid through percutaneouspenetrations is not of concern. Thus, either thoracoscopic trocarsleeves without fluid seals or percutaneous incisions may be utilizedfor instrument introduction into the thoracic cavity. Trocar sleeves aregenerally preferred, however, in order to provide an open passage intothe thoracic cavity, to protect adjacent tissue from injury resultingfrom contact with instruments, and to avoid damaging instruments,endoscopes, replacement valves, and the like when introduced into thethoracic cavity.

[0115] Referring now to FIGS. 11A-11D, access cannula 22 will bedescribed in greater detail. Access cannula 22 comprises a body 44having a proximal end 46, a distal end 48, and a passage 50 extendingtherebetween. Body 44 is configured to fit within an intercostal space Iwithout significant deflection of adjacent ribs R, usually having awidth of less than about 20 mm. Passage 50 is configured to facilitatepassage of replacement valve 36 therethrough. Replacement valve 36 mayhave a variety of configurations, but must have a diameter at leastequal to that of the patient's natural heart valve, a diameter whichcommonly exceeds the width of the intercostal spaces in the rib cage.Therefore, in order to avoid cutting or retracting the patient's ribs,replacement valve 36 is introduced edge-first through passage 50 ofaccess cannula 22, as described more fully below. To accommodate suchintroduction of replacement valve 36, passage 50 usually has across-sectional width w of about 12 mm to 20 mm, and a cross-sectionalheight h that is somewhat greater than cross-sectional width w, usually2-6 times cross-sectional width w, and preferably in the range of 25 mmto 50 mm. Passage 50 may have various cross-sectional shapes, includingoval, rectangular, race-track, and the like. This accommodates a varietyof replacement heart valves, including mechanical and biologicalprostheses, as well as homograft and allograft tissue valves. It will beunderstood, however, that certain replacement valves may be collapsibleor sufficiently small in size so that passage 50 in access cannula 22may have a round or square cross-section and still allow passage of thereplacement valve therethrough. However, a cross-sectional shape inwhich the height is greater than the width may still be advantageous toallow greater freedom of movement in manipulating the replacement valveand other instruments introduced through passage 50.

[0116] As shown in FIG. 11B, an obturator 52 is positionable in passage50 to facilitate introduction of access cannula 22 through the chestwall. Obturator 52 has a tapered distal end 54, a proximal end 56, and arim 58 near proximal end 56 for engaging proximal end 46 of cannula body44. Usually, obturator 52 is positioned in passage 50 of access cannula22, and the two are introduced through a small incision formed in anintercostal space in the chest wall. Obturator 52 is then removed frompassage 50.

[0117] As described briefly above, access cannula 22 may further includea suture organizing ring 30 mounted to its proximal end 46. Sutureorganizing ring 30 has a ring-shaped body 60 and a plurality of slots 62circumferentially spaced about body 60. Usually, between 16 and 32 ofslots 62 are provided, depending upon the type of replacement valve andsuturing technique to be utilized in the procedure. An elastomericretaining ring 64 is disposed in a circumferential channel in ring body60, and has a plurality of slits 66, best seen in FIG. 11D, aligned witheach slot 62. Slits 66 are provided with chamfers 68 along the topsurface of retaining ring 64 to facilitate positioning sutures withinslits 66 for retention therein. The function of suture organizing ring30 will be described in greater detail below.

[0118] Referring again to FIG. 2, once access cannula 22 and trocarsleeves 24 have been positioned in the patient's chest, endoscope 25 isintroduced through trocar sleeve 24D and camera 26 is connected to videomonitor 28 (FIG. 1). Endoscope 25 is manipulated so as to provide a viewof the right side of the heart, and particularly, a right side view ofthe left atrium. Usually, an endoscope of the type having an articulateddistal end, or a distal end disposed at an angle between 30° and 90°will be used, which is comnercially available from, for example, OlympusCorp., Medical Instruments Division, Lake Success, N.Y.

[0119] At this point in the procedure, if not previously accomplished,the patient is placed on cardiopulmonary bypass (CPB), the patient'sright lung is at least partially collapsed, and the patient's heart isarrested. Suitable techniques for arresting cardiac function andestablishing CPB without a thoracotomy are described incommonly-assigned. copending applications Ser. No. 07/991,188, filedDec. 15, 1992, Ser. No. 08/123,411, filed Sep. 17, 1993, Ser. No.08/159,815, filed Nov. 30, 1993, Ser. No. 08/162,742, filed Dec. 3,1993, and Ser. No. ______, attorney docket no. 14635-16-1/92001-2,entitled “System for Cardiac Procedures,” filed on the same day as thepresent application, all of which are incorporated herein by reference.

[0120] As illustrated in FIG. 3, CPB is established by introducing avenous cannula 70 into a femoral vein 72 in patient P and advancingvenous cannula 72 into the inferior vena cava 74 and/or into theinterior of heart H to withdraw deoxygenated blood therefrom. Venouscannula 70 is connected to a cardiopulmonary bypass system 76 whichreceives the withdrawn blood, oxygenates the blood, and returns theoxygenated blood to an arterial return cannula 78 positioned in afemoral artery 80.

[0121] A pulmonary venting catheter 79 may also be utilized to withdrawblood from the pulmonary trunk 77. Pulmonary venting catheter 79 may beintroduced from the neck through the interior jugular vein 106 or asubclavian vein and through superior vena cava 108, or from the grointhrough femoral vein 72 and inferior vena cava 74. Usually, a Swan-Ganzcatheter (not shown) is first introduced and positioned in pulmonaryartery 77 using well-known techniques, and pulmonary venting catheter 79is then introduced over the Swan-Ganz catheter. Blood is withdrawn frompulmonary trunk 77 through a port at the distal end of pulmonary ventingcatheter 79 and an inner lumen extending through the catheter outside ofthe patient's body. Pulmonary venting catheter 79 may further have oneor more balloons 81 at its distal end proximal to the distal port foroccluding pulmonary trunk 77.

[0122] An alternative method of venting blood from pulmonary trunk 77 isdescribed in U.S. Pat. No. 4,889,137, which is incorporated herein byreference. In the technique described therein, a catheter is positionedfrom the interior jugular vein in the neck through the right atrium,right ventricle, and pulmonary valve into the pulmonary artery 77. Thecatheter has a coil about its periphery which holds the pulmonary valveopen so as to drain blood from pulmonary trunk 77, thereby decompressingthe left side of the heart.

[0123] For purposes of arresting cardiac function, an aortic occlusioncatheter 82 is positioned in a femoral artery 84 by a percutaneoustechnique such as the Seldinger technique, or through a surgicalcut-down 86. The aortic occlusion catheter 82 is advanced, usually overa guidewire (not shown), until an occlusion balloon 88 at its distal endis disposed in the ascending aorta 90 between the coronary ostia 92 andthe brachiocephalic artery 94. Blood may be vented from ascending aorta90 through a port 95 at the distal end of the aortic occlusion catheter82 in communication with an inner lumen in aortic occlusion catheter 82,through which blood may flow to proximal end 96 of catheter 82. Theblood may then be directed to a blood filter/recovery system 98 toremove emboli, and then returned to the patient's arterial system viaCPB system 76.

[0124] When it is desired to arrest cardiac function, occlusion balloon88 is inflated by injecting inflation fluid, usually a mixture of salineand a radiographic contrast agent, from a syringe 100 connected toproximal end 96 of catheter 82, through an inflation lumen in catheter82 to the interior of occlusion balloon 88. Occlusion balloon 88 isexpanded until it completely occludes ascending aorta 92, blocking bloodflow therethrough. A cardioplegic fluid such as potassium chloride (KCl)is then delivered to the myocardium in one or both of two ways.Cardioplegic fluid may be delivered in an anterograde manner from acardioplegia pump 101 through an inner lumen in aortic occlusioncatheter 82 and a port distal to occlusion balloon 88 into the ascendingaorta upstream of occlusion balloon 88. Pressure in the aortic root ismeasured by a pressure measurement device 103 in communication with apressure lumen in catheter 82 having an opening distal to occlusionballoon 88. The cardioplegic fluid is then infused into the coronaryarteries and paralyzes the myocardium.

[0125] Alternatively, or in conjunction with such anterograde delivery,cardioplegic fluid may be delivered in a retrograde manner through aretroperfusion catheter 102 positioned in the coronary sinus 104.Retroperfusion catheter 102 may be positioned, usually over a guidewire(not shown), from the neck through the interior jugular vein 106 andsuperior vena cava 108, or from the groin through a femoral vein 72 andthe inferior vena cava 74. Retroperfusion catheter 102 may have one ormore balloons (not shown) at its distal end to enhance positioning andinfusion of cardioplegia into the coronary sinus. Cardioplegic fluid maythus be infused through the coronary veins into the capillary beds,paralyzing the myocardium.

[0126] In a preferred embodiment, the cardioplegic fluid consists of anaqueous KCl solution mixed with oxygenated blood at a ratio of fourparts blood to one part KCl solution. The aqueous KCl solution consistsof crystalloid KCl mixed with saline to have a concentration in therange of 10-50 mEq K⁺/liter, preferably 15-30 mEq K⁺/liter. A coolersuch as an ice bath (not shown) is used to cool the cardioplegic fluidto e.g. 3° C.-10° C., so as to maintain the heart at a low temperatureand to minimize demand for oxygen. This is usually accomplished withoutapplying external cooling to the heart as is generally applied inconventional open cardiac procedures. The cardioplegic fluid is infusedinto the ascending aorta through an opening at the distal end ofocclusion catheter 82 to maintain a pressure in the aortic root distalto the occlusion balloon sufficient to induce flow of fluid into thecoronary arteries through the coronary ostia. A pressure of about 60-80mmHg as measured through a pressure lumen in catheter 82 is usuallysufficient. Cardioplegic fluid is preferably delivered at a flowrate ofabout 250-350 ml/min. so as to deliver a total volume of 750-1000 ml inabout 2-4 minutes, although this may vary depending upon patientanatomy, physiological changes such as coronary dilation, and otherfactors. In pumping the cardioplegic fluid through the lumen in catheter82, the fluid should be subject to a pump pressure of no more than about300 mmHg to minimize damage to the blood component of the mixture. Heartcontractions will then cease, with circulation to the remainder of thepatient's body maintained by the CPB system. Cardioplegic fluid flow tothe patient's myocardium is maintained on a periodic basis, e.g., aboutevery 10-20 minutes for 2-4 minutes, so long as the myocardium is toremain paralyzed. A comprehensive description of cardioplegic techniquessuitable for use in the method of the invention is found in Buckberg,Strategies and logic of cardioplegic delivery to prevent, avoid, andreverse ischemic and reperfusion damage, J. Thorac. Cardiovasc. Surg.1987;93:127-39.

[0127] In addition to or instead of infusion of the blood/crystalloidcardioplegic solution, other techniques may be used to arrest heartcontractions. A more concentrated crystalloid KCl solution not mixedwith blood may be delivered through a lumen in occlusion catheter 82 athigher pressures than with a blood cardioplegic fluid mixture, sincewithout blood in the solution, there is no risk of hemolysis. Thisallows the inner lumen (as well as the overall catheter shaft) to be ofsmaller cross-sectional area while still providing the necessaryflowrate of fluid into the aortic root. However, the above bloodcardioplegia technique is presently preferred because it is generallybelieved to provide greater myocardial protection. In anotheralternative technique, the patient's body may be cooled in acold-temperature environment or by application of cold-packs to thechest to reduce the temperature of the myocardium sufficiently to inducefibrillation. The myocardium may be cooled directly by infusion of coldfluid such as cold blood or saline through the coronary arteries.Alternatively, electrical fibrillation may be accomplished by deliveringelectrical signals to the myocardium by means of electrodes placed onthe exterior surface of the heart or externally on the chest. However,cardiac arrest by means of fibrillation is generally less desirable thanchemical cardioplegic paralysis because there remains some degree ofheart motion which could make surgical intervention more difficult andbecause there is a significantly higher demand for oxygen, reducing thesafety and duration of the procedure.

[0128] The right lung may be collapsed using known techniques. Usually,a tube is introduced through the trachea into the right main stembronchus, and a vacuum is applied through the tube to collapse the lung.

[0129] Periodically during the procedure, it may be necessary todecompress the left side of the heart by removing blood and other fluidswhich have accumulated in the aortic root, left atrium and/or leftventricle and which have not been removed by the pulmonary arteryventing catheter (if utilized). To remove such fluids, suction may beapplied through an inner lumen in occlusion catheter 82 so as toaspirate fluids from the aorta, left ventricle, and or left atriumupstream of occlusion balloon 88. Aortic root pressure may be monitoredby pressure measurement device 103 via a separate lumen in catheter 82.Such venting is usually performed after each periodic infusion ofcardioplegic fluid and additionally as necessary to maintaindecompression of the left side of the heart. In some cases, ventingthrough occlusion catheter 82 may be sufficient to maintain left heartdecompression throughout the procedure, eliminating the need for apulmonary artery venting catheter.

[0130] Additional exemplary embodiments of an endovascular aorticpartitioning system according to the invention are illustrated in FIGS.26-34. The heart 410 of FIGS. 26 and 27 is positioned in the living bodyof a patient and is accessed percutaneously.

[0131] In order to induce cardioplegia in the heart while maintainingthe patient it is necessary to divert the patient's blood circulationthrough an extracorporeal cardiopulmonary by-pass system. This isachieved by isolating the heart 410 on both the venous and arterialsides using appropriate percutaneously inserted venous catheter 411,aortic balloon catheter 412, and if this catheter 412 doesn't haveprovision for arterial blood return, arterial catheter 439 (see FIG.28). The venous outflow and arterial inflow lumina of the catheters 411and 412 of the by-pass system are of sufficient cross sectional area toachieve standard blood flows to maintain the patient's systemiccirculation during the period of extracorporeal circulation.

[0132] In the case of the use of a single venous double-balloonedcatheter 411, as is shown in FIG. 26, the catheter 411 is insertedthrough the femoral vein preferably. A suitable guide wire is initiallyinserted and the catheter 411 is then introduced in known manner underfluoroscopic guidance. The catheter 411 includes a pair of separatelyinflatable balloons 414 and 415 each connected to a balloon inflationcontrol device (not shown) through suitable lumina in the catheter 411.The balloon 414 is adapted to occlude the superior vena cavae 416 whilethe balloon 415 is adapted to occlude the suprahepatic inferior venacavae 417. A blood withdrawal lumen in the catheter 411 has an inletorifice 418 flush with the balloon 414, to avoid venous collapse duringblood flow into the catheter 411, and a series of inlet slots 419 in theinferior vena cavae. Blood drawn into the inlets 418 and 419 enters acommon single lumen. Blood drawn into the by-pass system through thecatheter 411 is oxygenated and returned to the patient in a manner whichwill be hereinafter described.

[0133] A separate lumen in the catheter 411 opens into the right atrium422 through aperture 421 to allow evacuation of blood from the rightheart and the infusion of saline to induce topical cooling and/or toimprove visual acuity within the right heart.

[0134] In use, after the catheter 411 has been positioned the balloonsmay be inflated or deflated to vary the rate of venous return to theright atrium 422 and therefore the degree of decompression of the leftheart. Venous drainage may be effected by gravitational drainage or byapplying a degree of negative pressure to assist flow into the pumpoxygenator. It will be appreciated that the distance between theballoons 414 and 415 will need to be correct for a given patient andthis may be assessed by X-ray examination to allow selection of anappropriately sized catheter. Alternatively separate catheters 411 b and411 c could be used, as is shown in FIG. 34a, for the inferior andsuperior vena cavae, the cannula 411 b being introduced as has beendescribed above and the cannula 411 c being introduced through thejugular or subclavian vein. It will also be appreciated that for simpleoperations not requiring complete occlusion of the right atrium it ispossible to merely insert a simple catheter 411 into the right atrium todraw blood into the by-pass system as is seen in FIG. 27. Positioningunder fluoroscopic guidance is not essential in this case.

[0135] The catheter 412 is positioned in the manner described above withits free end located in the ascending aorta 423. The catheter 412 is sopositioned by insertion preferably through the femoral artery 424 andvia the descending aorta 425 as is seen in FIG. 28.

[0136] If desired a fluoroscopic dye may be introduced into the aorticroot 426 through the catheter 412 for accurate positioning of the tip ofthe catheter 412 relative to the aortic root 426 and the coronary ostia.

[0137] The catheter 412 carries at its free end a balloon 427. Theballoon 427 is arranged to be inflated with saline from an inflationcontrol device 428 of known type through a lumen in the catheter 412.The device 428 is fitted with a pressure gauge 429 to allow the operatorto control the inflation of the balloon 427. The pressure of the fullyinflated balloon 427 should be of the order of 350 mmHg so as to besufficient to effectively occlude the aorta and to prevent the balloonmoving while not being so great as to cause damage to the aortic wall.The balloon 427 should have a maximum diameter sufficient to occlude theaorta and for this purpose the maximum diameter should be about 35 mm.The balloon 427 should have a length of about 40 mm so as not to be solong as to occlude or impede blood flow to the coronary arteries or tothe brachiocephalic, subclavian or carotid arteries. If necessary in anygiven patient the required length and diameter of the balloon may bedetermined by angiographic, X-ray examination or echocardiography and anappropriately sized catheter selected on that basis.

[0138] The balloon 427 is preferably connected to the lumen 432 throughwhich it is inflated at the end of the balloon 427 distal to the tip ofthe catheter 412 through orifice 431 (see FIG. 30). This allows the tipof the catheter to contain fewer lumina than the remainder of thecatheter. Accommodation of the deflated balloon around the tip of thecatheter is thus possible without adding to the diameter of the tip ascompared with the rest of the catheter 412.

[0139] The catheter 412 includes a plurality of lumina (see FIGS. 31 and32). In addition to the balloon inflation lumen 432 there is at least asingle venting cardioplegia lumen 433 of circular cross-section. Theremay be a separate and extra circular lumen 434 for instrumentation. Iftwo lumens are present the venting/cardioplegia lumen may be circular orcrescent shaped in cross-section (FIG. 31a, 31 b). The diameter of thevarious lumina should be as small as practicable commensurate with theintended use. In addition, there may be a continuous lumen 435 throughwhich arterial blood is returned from the by-pass. This may flow out ofthe catheter 412 through an orifice in the region of the external iliacartery. In alternative embodiments of the invention such as shown inFIGS. 28 and 33b the arterial return lumen 435 may comprise its owncatheter 439 of known type introduced into the other femoral artery orsome other suitable artery.

[0140] In use the catheter 412 is introduced percutaneously by punctureor cutdown as has been described and once blood flow through the by-passis established (including systemic cooling) flows are reduced and theballoon 425 is inflated. Flows are then returned to the operating levelsand a suitable cardioplegic agent is introduced into the aortic root.Once the full volume of cardioplegic agent has been given and cardiacarrest achieved, the lumen is then used to vent the heart. Venting ofthe left ventricle may be effected by providing an extended cannula 438projecting from lumen 433 into the left ventricle (see FIG. 27) or bysimply applying negative pressure to the venting lumen 433 of the aorticcatheter. The heart may then be operated on or examined by insertion ofinstrumentation 437 such as a cardioscope or a laser into the heartthrough the lumen 434 or through atrial trocars. Alternatively, with theheart on by-pass as described above the heart can be approached by anopen method by an incision other than median sternotomy.

[0141] With cardiopulmonary bypass established, cardiac functionarrested, and the right lung collapsed, the patient is prepared forsurgical intervention within the heart H. A preferred technique ofmitral valve replacement will be described in detail here. Referringagain to FIG. 2, a surgical cutting instrument such as angled scissors110, as well as a grasping instrument such as grasping forceps 112, areintroduced through access cannula 22 or through trocar sleeves 24A, 24B.Angled scissors 110 and forceps 112 are used to form an opening in thepericardium, providing access to the right side of the left atrium.

[0142] Angled scissors 110 are illustrated more clearly in FIGS.12A-12D. Angled scissors 110 include a shaft 114 having a distal end116, a proximal end 118, and an actuator 120 attached to proximal end118. Shaft 114 of angled scissors 110 has a length selected to allowintervention within left atrium LA of heart H, and is usually at leastabout 15 cm in length and preferably 20 cm to 35 cm in length. Actuator120 includes a movable arm 122 pivotally coupled to a stationary arm124. A linkage 126 connects movable arm 122 to a push rod 128 extendingslidably through shaft 110. By pivoting movable arm 122 toward shaft114, push rod 128 is translated distally. A stationary blade 130 ismounted to distal end 116 of shaft 114, and a movable blade 132 ispivotally mounted to stationary blade 130. Push rod 128 is linked tomovable blade 132 such that distal movement of push rod 128 pivotsmovable blade 132 toward stationary blade 130. Blades 130. 132 may bemounted at various angles relative to shaft 114, as illustrated in FIGS.12B-12D. A flush port (not shown) may also be provided in shaft 114 fordelivering a flushing solution such as saline to distal end 116 toremove fluid and/or debris from blades 130, 132 or from the surgicalsite.

[0143] In addition to angled scissors 110, a retractable knife 134,illustrated in FIG. 13, may be used for various cutting purposes.Retractable knife 134 comprises a shaft 136 having a distal end 138 anda proximal end 140. A handle 142 is attached to proximal end 140, towhich an actuator 144 is slidably mounted. A push rod (not shown) iscoupled to actuator 144 and extends slidably through shaft 136. A knifeblade 146 is slidably mounted at distal end 138 of shaft 136 and islinked to the push rod, such that sliding actuator 144 proximallyretracts knife blade 146 within a sheath 148 mounted to distal end 138.Alternatively, knife blade 146 may be fixed to shaft 136, and sheath 148slidably mounted to shaft 136 and linked to the push rod, such thatsheath 148 may be retracted and extended over knife blade 146 by slidingactuator 144.

[0144] Grasping forceps 112 are illustrated in FIGS. 14A-14B. Graspingforceps 112 have a construction much the same as that of angled scissors110, with an actuator 150 translating a push rod 152 slidably disposedin a shaft 154. A stationary jaw 158 is fixed to a distal end 156 ofshaft 154, and a movable jaw 160 is slidably mounted to shaft 154. Pushrod 152 is linked to movable jaw 160, such that translation of push rod152 by actuator 150 closes movable jaw 160 against stationary jaw 158.Grooves or other textural features may be provided on the inner surfacesof jaw 158 and/or jaw 160 to improve grip upon tissue.

[0145]FIG. 4 illustrates the view into the thoracic cavity throughpassage 50 of access cannula 22. Angled scissors 110 aided by graspingforceps 112 are shown cutting through the right side of left atrium LAto form an atriotomy 162. Atriotomy 162 is formed along dotted line 164anterior to right pulmonary veins PV. A completed description oftechniques for forming such an atriotomy is found in Kirklin andBarratt-Boyes, Cardiac Surgery, pp. 329-340, the disclosure of which hasbeen incorporated herein by reference. Usually, atriotomy 162 will beformed under visualization by means of endoscope 25 (FIGS. 1 and 2),although direct viewing is possible through passage 50 of access cannula22, or through a trocar sleeve 24.

[0146] Upon completion of atriotomy 162, the wall of left atrium LA onthe anterior side of atriotomy 162 is retracted anteriorly by means ofthoracoscopic retractor 40, as illustrated FIGS. 1 and 5. Thoracoscopicretractor 40, illustrated more clearly in FIG. 15, includes a shaft 166having a distal end 168, a proximal end 170, and an inner lumen 172therebetween. A pair of finger rings 174 is mounted to proximal end 170of shaft 166. A guide 175 is also mounted to proximal end 170 having achannel 176 extending therethrough. A sliding rod 178 extends throughchannel 176 and has a plurality of teeth 180 on a lateral surfacethereof which are engaged by a pawl 182 pivotally mounted to guide 175and biased by a spring (not shown) against teeth 180. Sliding rod 178has a proximal end 184 to which a thumb ring 186 is attached, allowingthumb ring 186 to be drawn toward finger rings 174. A push rod 188 isslidably disposed in lumen 172 of shaft 166 and is attached at itsproximal end 190 to sliding rod 178. Three rake arms 192 are pivotallycoupled to shaft 166 within a transverse slot 194 at distal end 168.Rake arms 192 each have a hooked distal end 193 for engaging andretracting tissue. The distal end of push rod 188 slidably engages rakearms 192 within a slot 196 in each rake arm. In this way, by slidingpush rod 188 distally, rake arms 192 collapse in an overlappingconfiguration suitable for introduction through one of trocar sleeves24. Once rake arms 192 are introduced into the thoracic cavity, they maybe expanded by pulling thumb ring 186 relative to finger rings 174.

[0147] Referring again to FIG. 5, retractor 40 is introduced into thethoracic cavity through trocar sleeve 24 and rake arms 192 are deployedinto their expanded configuration. Retractor 40 is manipulated so thathooked ends 193 of rake arms 192 engage the wall of left atrium LA onthe anterior side of atriotomy 162. Retractor 40 is then pulled in theanterior direction to retract the wall of left atrium LA, openingatriotomy 162 and exposing the patient's mitral valve MV within the leftatrium LA. A conventional stopcock, cam lock, or other clamping device(not shown) may be provided on trocar sleeve 24 to lock retractor 40 inposition, or shaft 166 may be provided with an adjustable collar (notshown) for engaging trocar sleeve 24 to maintain retractor 40 inposition.

[0148] It will be understood that retractor 40 illustrated in FIGS. 1, 5and 15 is merely exemplary of the various means that may be used forretraction of left atrium LA. Another suitable means of retraction isdescribed in published European patent application numberPCT/US92/06186, the complete disclosure of which is incorporated hereinby reference. That application describes a clip which may be applied totissue by means of an introducer, and a flexible cable assembly attachedto the clip which may be used to apply traction to the clip from outsideof the patient's body. The clip may be applied to the wall of the leftatrium LA on the anterior side of atriotomy 162 with the cable extendingthrough a trocar sleeve 24, whereby atriotomy 162 is retracted open byapplying traction to the cable. The cable may be attached to thepatient's body, to the surgical drapes, or to another support structureoutside of the body to maintain the atriotomy open during the procedure.Alternatively, one or more sutures (not shown) may be applied to thewall of left atrium LA anterior to atriotomy 162. The free ends of thesutures may be applied to an internal structure in the thoracic cavity,or withdrawn from the thoracic cavity through a puncture or a trocarsleeve 24 and attached to the patient's body or to the surgical drapes,thereby opening atriotomy 162. Other suitable means of retractioninclude devices having a collapsible and expandable frame (not pictured)which is insertable within atriotomy 162. When deployed, the frame urgesthe opposing sides of atriotomy 162 away from each other, and maintainsthe atriotomy open throughout the procedure until the device is removed.

[0149] With atriotomy 162 retracted open, the interior of heart H isaccessible for the performance of an interventional procedure therein.Instruments may be introduced through access cannula 22 or trocarsleeves 24 and through atriotomy 162 to perform a procedure within leftatrium LA. Additionally, such instruments may be extended through mitralvalve MV into the left ventricle, or from the left ventricle through theaortic valve into the ascending aorta for inspection or interventiontherein. In this way, the aortic valve may be repaired or replaced usingtechniques much like the mitral valve repair and replacement techniquesdescribed below.

[0150] When replacing mitral valve MV, it is often desirable to cut orremove all or a portion of the mitral valve leaflets VL. For thispurpose, grasping forceps 112 may be used to grasp valve leaflet VLwhile angled scissors 110 and/or knife 134 are used to excise valveleaflet VL from the valve annulus VA. All or part of one or both valveleaflets VL may be cut or removed in this way. When removing valveleaflets VL, however, it is generally desirable to avoid permanentlycutting or removing the chordae tendonae and papillary muscles (notshown) attached to the left ventricle. It has been found that apatient's chordae tendonae and papillary muscles may contribute toproper cardiac function even when a patient's natural valve has beenreplaced with a replacement valve.

[0151] At this point, it is usually necessary to size valve annulus VAso as to select a replacement valve 36 of the proper size for patient P.Various means may be used for sizing, but in one embodiment a sizingdisk is introduced through access cannula 22, and the diameter of thesizing disk is compared to that of valve annulus VA. Preferred devicesand methods for sizing valve annulus VA are described more fully below.

[0152] Various types of replacement valves are available for replacementof the mitral valve, and there are various ways of securing thesereplacement valves within the patient's heart. One common means ofreplacement valve attachment is suturing the prosthesis to the patient'snatural valve annulus. Referring to FIG. 6, after valve leaflets VL havebeen removed, a plurality of sutures 198 are applied to valve annulusVA, under visualization by means of endoscope 25 (FIGS. 1-2) and/or bydirect vision through passage 50 of access cannula 22. Each end of eachsuture 198 is attached to a curved needle 200. At least one and usuallytwo needle drivers 202 are introduced into the thoracic cavity throughtrocar sleeves 24 and/or access cannula 22. A first of needle drivers202 is used to drive a tip of needle 200 through valve annulus VA, whilea second of needle drivers 202 is used to grasp the tip of needle 200and pull it completely through valve annulus VA. After being applied tovalve annulus VA, each suture 198 is withdrawn from the thoracic cavitythrough passage 50 of access cannula 22, and placed in one of slots 62in organizing ring 30. Because a needle 200 is attached to both ends ofeach suture 198, each needle 200 may be driven through valve annulus VAin a single direction. then withdrawn from the thoracic cavity throughpassage 50 of access cannula 22. Preferably, each suture 198 ispositioned within a slit 66 in retaining ring 64 (FIGS. 11A-11D) tofrictionally engage the suture and keep it within slot 62.

[0153] Various types of stitches may be used in applying sutures 198 tovalve annulus VA. In an exemplary embodiment, a “mattress” suturetechnique is used, wherein each needle 200 is driven through valveannulus VA from the ventricular side toward the atrial side of valveannulus VA. Alternatively, an “everting mattress” suture technique isused, wherein each needle 200 is driven through valve annulus VA fromthe atrial side toward the ventricular side of valve annulus VA. Variousother types of stitches may also be used, depending upon the type ofreplacement valve to be utilized and the position in which it is to bemounted to valve annulus VA.

[0154] FIGS. 16A-16B illustrate the construction of needle drivers 202in greater detail. Needle drivers 202 include a shaft 204 having adistal end 206 and a proximal end 208. An actuator 210 is attached toproximal end 208, and is constructed as described above in connectionwith FIG. 12A. Actuator 210 translates a push rod 212 extending throughshaft 204. A stationary jaw 214 is fixed to distal end 206 of shaft 204,and a movable jaw 216 is pivotally mounted to stationary jaw 214.Movable jaw 216 is linked to push rod 212, whereby distal movement ofpush rod 212 closes movable jaw 216 against stationary jaw 214. Carbidesurfaces as well as grooves or other textural features may be providedon the inner surfaces of jaws 214, 216 to enhance gripping of needles200. Further, a locking mechanism (not shown) may be included onactuator 210 to lock jaws 214, 216 in the closed position.

[0155] Referring to FIG. 7, once all of sutures 198 have been withdrawnfrom the thoracic cavity and placed in slots 62 of organizing ring 30,the sutures are applied to replacement valve 36, held in position byintroducer 38. Replacement valve 36 may be any of a variety ofcommercially available prostheses, including mechanical andbioprosthetic, stented and unstented, as described in Bodnar and Frater.Replacement Cardiac Valves, pp. 4-7, which has been incorporated hereinby reference, and in Jamieson, “Modern Cardiac ValveDevices—Bioprostheses and Mechanical Prostheses: State of the Art,” J.Card. Surg. 8:89-98 (1993). Mechanical valves may be of the caged balltype such as the Starr-Edwards valve (Baxter Healthcare Corp., EdwardsCVS Div., Irvine, Calif.), the tilting disk type such as the MedtronicHall valve (Medtronic, Inc., Minneapolis, Minn.), the Bjork-ShileyMonostrut valve (Shiley, Inc., Irvine, Calif.), the Omniscience® valve(Omniscience Medical Inc., Grove Heights, Minn.), as well as thebileaflet type such as the St. Jude Medical valve (St. Jude Medical,Inc., St. Paul, Minn.), the Baxter Duromedics valve (Baxter HealthcareCorp., Edwards CVS Div., Irvine, Calif.), the Carbomedics valve(Carbomedics, Inc., Austin, Tex.), or the Sorin valve (Sorin Biomedica,Saluggia, Italy). Bioprosthetic valves may be porcine aortic valves suchas the Hancock II bioprosthesis (Medtronic, Inc., Minneapolis, Minn.),the Carpentier-Edwards supraannular bioprosthesis (Baxter HealthcareCorp., Edwards CVS Div., Irvine, Calif.), the Carpentier-Edwardsstentless bioprosthesis (Baxter Healthcare Corp., Edwards CVS Div.,Irvine, Calif.), the St. Jude-Bioimplant bioprosthesis (St. JudeMedical, Inc., St. Paul, Minn.), or the Medtronic Intact® bioprosthesis(Medtronic, Inc., Minneapolis, Minn.), as well as pericardial valvessuch as the Mitroflow bioprosthesis (Mitroflow International, Inc.,Richmond, British Columbia, Canada), or the Carpentier-Edwardspericardial bioprostheses (Baxter Healthcare Corp., Edwards CVS Div.,Irvine, Calif.). The invention also facilitates valve replacement withhomografts and allografts, as well as with a variety of replacementvalves not specifically listed here.

[0156] In an exemplary embodiment, the invention facilitates replacementof a patient's mitral valve with a mechanical bileaflet replacementvalve such as the St. Jude Medical valve, illustrated in FIGS. 17A-17C.In this embodiment, replacement valve 36 comprises a ring-shaped frame218 and a pair of leaflets 220 pivotally mounted to frame 213. In theopen configuration illustrated in FIGS. 17A-17B, leaflets 220 are nearlyparallel to each other, providing a flow passage 222 through which bloodmay flow in the direction of arrows 224. In the event of fluid pressureagainst the inner faces 226 of leaflets 220, leaflets 220 pivot into aclosed configuration. blocking flow passage 222. A sewing ring 228 isattached to frame 218 to which sutures 198 may be applied for securingreplacement valve 36 in the heart.

[0157] As illustrated in FIGS. 17B-17C, replacement valve 36 may bemounted to introducer 38 for introduction into the heart through passage50 of access cannula 22. Replacement valve 36 may have various sizesaccording to the size of the mitral valve being replaced. However, theouter diameter of sewing ring 228 is usually about 19 mm to 35 mm,which, for most adult patients, is larger than the width of the third,fourth, fifth or sixth intercostal spaces, which range from 15 mm to 20mm in width. The height of replacement valve 36, on the other hand, issmaller than the width of these intercostal spaces, usually being about8 mm to 15 mm. Therefore, passage 50 is configured to allow replacementvalve 36 to pass through it in an edge-first orientation, as illustratedin FIG. 17C.

[0158] Introducer 38 will now be described with reference to FIGS.18-20. Introducer 38 includes a shaft 230 having a distal end 232, aproximal end 234, and an inner lumen 236 therebetween. Shaft 230 has alength selected to allow placement of replacement valve 36 in the mitralvalve position within the patient's heart from outside of the patient'sthoracic cavity, and is usually at least about 20 cm in length, andpreferably about 25 cm to 35 cm in length. A handle 238 is attached toproximal end 234, and a rotatable knob 240 is mounted to handle 238 forpivoting the replacement valve 36 relative to shaft 230. A pull ring 242extends proximally from pivot knob 240 for releasing replacement valve36 from introducer 38. As best seen in FIGS. 20A-20B, push rod 244extends through inner lumen 236, and is coupled at its distal end 248 toa pivot 250 which is pivotally mounted within a slot 252 at distal end232 of shaft 230. A shank 254 extends distally from pivot 250 and hasthreads or other means for attachment to a valve holder 255 forreplacement valve 36. Knob 240 is fixed to a threaded shaft 256 receivedwithin a threaded bore 258 in handle 238, whereby rotation of knob 240translates threaded shaft 256 distally or proximally, depending upon thedirection of rotation. Push rod 244 has a proximal end 260 which engagesa distal end 262 of threaded shaft 256. A spring 264 biases push rod 244in a proximal direction against distal end 262. In this way, rotation ofknob 240 pulls or pushes push rod 244, thereby pivoting pivot 250 suchthat shank 254 extends either distally or laterally.

[0159] Referring to FIGS. 19A-19G, valve holder 255 includes astationary arm 266 attached to shank 254, and a movable arm 268pivotally mounted to stationary arm 266. Each of arms 266, 268 has anannular channel 270 configured to engage frame 218 of replacement valve36 within flow channel 222 (FIG. 17A). Arms 266, 268 are furtherdimensioned and configured for introduction through passage 50 of accesscannula 22 when replacement valve 36 is held in channels 270. Asillustrated in FIG. l9A, when attached to shank 254 on introducer 38,valve holder 255 may be pivoted in the direction of arrow 272 byrotation of knob 240. In this way, the replacement valve 36 held byholder 255 may be introduced edge-first through passage 50 in accesscannula 22, then pivoted approximately 90° to an orientation suitablefor attachment in the mitral valve position within heart H.

[0160] To facilitate releasing replacement valve 36 from holder 55 froma location outside of the patient's body, a pull wire 274 is coupled tomovable arm 268 by, for example, an anchor ball 276 disposed within anaperture 278 (see FIG. 20A). Pull wire 274 extends through an innerlumen (not shown) in push rod 244, and is attached at its proximal end280 to pull ring 242. A spring 282 within an aperture 284 in knob 240biases pull ring 242 in a distal direction. In this way, pulling on pullring 242 pivots movable arm 268 as shown in FIG. 19C, allowingreplacement valve 36 to be removed from channels 270. Anchor ball 276and/or pull ring 242 may be configured so as to be removable from pullwire 244, allowing valve holder 255 to be removed from introducer 38 bydecoupling arm 266 from shank 254.

[0161] In order to keep replacement valve 36 on holder 255 when holder255 is not attached to introducer 38, a pair of holes 286 are providedin arm 266 in alignment with a corresponding pair of holes 288 in arm268. When replacement valve 36 has been placed on holder 255, a suture(not shown) may be tied through holes 286, 288 to prevent pivoting ofarm 268, thereby retaining replacement valve 36 on holder 255. Onceholder 255 has been attached to introducer 38, the suture may beremoved, allowing arm 268 to pivot in response to rotation of knob 240.

[0162] It will frequently be desirable for valve holder 255 andreplacement valve 36 to be pre-assembled, sterilized, and packagedtogether in a single sterile pack. In this way, upon opening the sterilepack in the operating room, the replacement valve 36 and holder 255 areready for immediate surgical use. Further, it may be desirable forintroducer 38 to be sterilized with replacement valve 36 and included inthe same sterile pack. In such cases, holder 255 may be integrated withand non-removable from introducer 38, with replacement valve 36 beingmounted to arms 266, 268 at the distal end of introducer 38 within thesterile pack. Alternatively, introducer 38 may be a reusable devicewhich is attached to holder 255 and replacement valve 36 in theoperating room at the time of the procedure.

[0163] As mentioned above, in order to select a replacement valve 36which is of the appropriate size for patient P, valve annulus VA isusually sized prior to applying sutures 198 to valve annulus VA. Sizingmay be accomplished in various ways, but in an exemplary embodiment, isperformed by means of a sizing disk 290, illustrated in FIGS. 21-23,pivotally attached to introducer 38. Sizing disk 290 may be pivotedapproximately 90° relative to shaft 230 of introducer 38, from anedge-first orientation suitable for introduction through access cannula22, to a face-first orientation suitable for sizing valve annulus VA. Asshown in FIGS. 22 and 23, sizing disk 290 is configured for attachmentto shank 254 of introducer 38, preferably by means of a threaded hole292. A notch 294 is provided in a proximal portion of disk 290 throughwhich distal end 232 of shaft 230 may extend when disk 290 is in theedge-first orientation. An aperture 296 is disposed in the middle ofdisk 290 through which distal end 232 of shaft 230 may extend when disk290 is in the face-first orientation. Preferably, a plurality ofinterchangeable sizing disks 290 of various diameters are provided forthe procedure, allowing various sizing disks 290 to be introduced intoheart H and compared with valve annulus VA until the diameter of thesizing disk corresponds to that of valve annulus VA.

[0164] In place of sizing disk 290, an expandable balloon or basket maybe used for sizing valve annulus VA. Fluoroscopy, transesophagealechocardiography (TEE), epicardial or trans-thoracic ultra-sonography,or angiography may also be used to facilitate sizing valve annulus VA.

[0165] When the size of valve annulus VA has been identified, sizingdisk 290 may be removed from introducer 38 and replaced by a replacementvalve 36 of the appropriate size, mounted on holder 255. Introducer 38may then be clamped to support stand 34 with replacement valve 36positioned between first organizing ring 30 and second organizing ring32, as illustrated in FIG. 7.

[0166] Sutures 198 are applied to replacement valve 36 by passingneedles 200 through sewing ring 228 using needle drivers 202. Sutures198 are then positioned in circumferentially spaced positions on secondorganizing ring 32. Second organizing ring 32 comprises, as illustratedin FIGS. 24A-24C, an inner ring 298 fixed to support stand 34, and anouter ring 300 rotatably mounted to inner ring 298. An elastomericretaining ring 302 is disposed in an annular channel 304 in inner ring298. Radial pins 303 are fixed to inner ring 298 and extend throughslots 305 in outer ring 300, thereby limiting the rotation of outer ring300 relative to inner ring 298. A plurality of slots 306 are disposed incircumferentially spaced positions about inner ring 298, and acorresponding number of slots 308 alignable with slots 306 are disposedin outer ring 300. Retaining ring 302 has a plurality of slits 310 whichare aligned with slots 306 in inner ring 298. A clamp 312 for clampingshaft 230 of introducer 38 is disposed on an extension 314 fixed tosupport stand 34.

[0167] After being applied to replacement valve 36, sutures 198 may bepositioned within inner slots 306, slits 310, and outer slots 308. Onceall of sutures 298 have been applied to replacement valve 36 andpositioned in organizing ring 32, outer ring 300 may be rotated relativeto inner ring 298, thereby locking sutures 298 in position.

[0168] Referring now to FIG. 8A, replacement valve 36 may then beintroduced into the left atrium LA by advancing introducer 38 throughpassage 50 of access cannula 22. Replacement valve 36 is oriented onintroducer 38 so as to be introduced edge-first through passage 50. Asreplacement valve 36 is advanced into the thoracic cavity, organizingring 32 maintains tension on sutures 198, allowing replacement valve 36to slide along sutures 198. Introducer 38 is advanced through atriotomy162 so that replacement valve 36 is disposed within left atrium LA.Replacement valve 36 is then pivoted on introducer 38 by rotating knob240, so that sewing ring 228 of replacement valve 36 (FIG. 17A) may bealigned with valve annulus VA.

[0169] Introducer 38 is then advanced further into left atrium LA so asto position replacement valve 36 against or within valve annulus VA, asillustrated in FIG. 8B. Square or overhand knots are then formed insutures 198 outside of the patient's thoracic cavity, and the knots arepushed by a knot pusher 316 through passage 50 and atriotomy 162 towardsewing ring 228 of replacement valve 36.

[0170] While knot pusher 316 may have a variety of configurations, anexemplary embodiment is illustrated in FIGS. 25A-25B. Knot pusher 316comprises a shaft 318 having a distal end 320 and a proximal end 322, towhich is connected an actuator 324 constructed like actuator 120described above in connection with FIG. 12A. Actuator 324 translates apush rod 326 extending through shaft 318. A pair of movable jaws 328 arepivotally mounted to distal end 320 of shaft 318, and are coupled topush rod 326 such that proximal movement of push rod 326 opens jaws 328.A notch 330 at the distal end of each jaw 328 is configured to receive asuture 198.

[0171] In use, a first free end of a suture 198 is tied in a loop orslip knot over a second free end of suture 198, and jaws 328 arepositioned just proximal to the knot. Jaws 328 are then opened such thateach force end of suture 198 is positioned within a notch 330 at thedistal end of jaws 328 and the slip knot is disposed centrally betweenjaws 328. While holding tension on the free ends of the sutures outsidethe thoracic cavity, knot pusher 316 is advanced distally, pushing theslip knot through passage 50 of access cannula 22 and atriotomy 162until the slip knot engages sewing ring 228 of replacement valve 36.

[0172] Referring now to FIG. 9, when a plurality of knots 332 (usually 5to 8) have been tied and pushed against sewing ring 228 by knot pusher316, knots 332 are cinched down tightly, and free ends 334 are trimmedusing scissors 110 or other cutting device.

[0173] It will be understood to those to ordinary skill in the art thatthe thoracoscopic devices and methods disclosed above for tissuemanipulation, retraction, cutting, suturing, and the like may be used toaccomplish procedures such as annuloplasty, commissurotomy, quadrangularresection, shortening and reattachment of chordae tendonae, and variousother valve repair procedures. To perform annuloplasty, valve annulus VAis contracted by suturing a portion of the valve annulus so as tooverlap an adjacent portion, or by attaching a prosthetic annuloplastydevice such as a Carpentier or Duran annuloplasty ring (not shown) tovalve annulus VA to reduce its diameter. To perform commissurotomy, thevalve leaflets VL are separated by cutting between them where they havefused together due to calcification or disease. To perform quandrangularresection, valve leaflets VL are shortened or narrowed by excising aportion of one or more leaflets VL, and reattaching the remainingportions of the leaflet by suturing. The chordae tendonae (not shown),which act as resilient springs between valve leaflets VL and thepapillary muscles (not shown) attached to the heart wall in the leftventricle LV, may be shortened by excising a portion thereof andreattaching the ends of the remaining portions by suturing. Similarly,severed chordae tendonae may be restored by reattachment of the severedends with sutures. Open-chest techniques for performing such proceduresare described in detail in Kirklin and Barratt-Boyes, Cardiac Surgery,pp. 329-340, the disclosure of which has been incorporated herein byreference.

[0174] When the valve replacement or other surgical procedure in leftatrium LA is completed, atriotomy 162 is closed. Sutures, thoracoscopicstaples or other types of closure devices may be used for this purpose.In one embodiment, illustrated in FIG. 10, atriotomy 162 is closed bysuturing, wherein needle drivers 202 are introduced through trocarsleeves 24 and/or access cannula 22, and a suture 336 having a needle338 attached to an end thereof is used to sew up atriotomy 162 usingconventional suturing techniques. Before and/or during closure, asuction/irrigation tube (not shown) is usually introduced through atrocar sleeve 24 and into left atrium LA or left ventricle LV to removeany air therein and to fill the heart chambers with a saline solution.

[0175] After atriotomy 162 has been closed, any remaining instrumentsare removed from the thoracic cavity. A chest tube may be introducedthrough one of trocar sleeves 24 to facilitate evacuation of the pleuralcavity. Access cannula 22 and trocar sleeves 24 are then removed fromthe chest wall, and the incisions or penetrations through which theywere introduced are closed, usually by suturing or stapling.

[0176] The patient's lung may then be reinflated, and cardiac functionmay be restarted. As described in copending application Ser. No.07/991,188, which has been incorporated herein by reference, infusion ofcardioplegic fluid through aortic occlusion catheter 82 and/orretroperfusion catheter 102 is discontinued, and a saline solution isinfused through one or both of these catheters to irrigate the heart andcoronary arteries (see FIG. 3). The saline solution, along with blood,other fluids, air, thrombus, and other emboli within the heart orcoronary arteries are then aspirated through the inner lumen of aorticocclusion catheter 82, as well as through venous cannula 70 and/orpulmonary venting catheter 79. Occlusion balloon 88 on aortic occlusioncatheter 82 is then deflated, allowing warm, oxygenated blood to flowinto the coronary arteries to perfuse the myocardium. Cardiaccontractions will usually begin soon thereafter. In some cases,electrical defibrillation may be necessary to help restore cardiacfunction. Aortic occlusion catheter 82 and retroperfusion catheter 102may then be removed from the patient. Cardiopulmonary bypass is thendiscontinued, and arterial cannula 78, venous cannula 70, and pulmonaryventing catheter 79 are removed from the patient.

[0177] In addition to performing mitral valve repair and replacement,the techniques of the invention also facilitate surgical interventioninto other regions of the heart and great vessels. The devices andmethods described above may be used to form an opening directly into theleft ventricle, right atrium, or right ventricle, or into a great vesselsuch as the aorta, superior vena cava, inferior vena cava, pulmonaryartery, or pulmonary vein, for surgical intervention in such cavities.For example, a penetration may be made in the wall of the aorta, and theaortic valve may be repaired or replaced with a prosthesis, usingtechniques and devices like those described above for mitral valvereplacement. Moreover, the devices and methods of the invention alsofacilitate intracardiac procedures such as repair of atrial orventricular septal defects, electrophysiological mapping and ablation ofthe myocardium, myocardial drilling, and other procedures. Furthermore,devices may be introduced through an opening into the heart or greatvessel and advanced therefrom into vessels such as the coronary arteriesto perform procedures such as angioplasty, atherectomy, coronary arterybypass grafting, or treatment of aneurysms.

[0178] While the above is a complete description of the preferredembodiments of the invention, various alternatives, modifications andequivalents may be used. Therefore, the above description should not betaken as limiting the scope of the invention, which is defined by theappended claims.

What is claimed is:
 1. A method of closed-chest surgical interventionwithin an internal cavity of a patient's heart or great vessel, themethod comprising: establishing cardiopulmonary bypass; arresting thepatient's heart; viewing an internal portion of the patient's chestthrough a scope extending through a percutaneous intercostal penetrationin the patient's chest; forming an internal penetration in a wall of theheart or great vessel using cutting means introduced through apercutaneous intercostal penetration in the patient's chest; andintroducing an interventional tool through a percutaneous intercostalpenetration and through the internal penetration to perform a surgicalprocedure within the internal cavity under visualization by means ofsaid scope.
 2. The method of claim 1 wherein the patient's heart isarrested by occluding the patient's aorta between the patient's coronaryarteries and the patient's brachiocephalic artery with an expandablemember on a distal end of an endovascular catheter, and perfusing thepatient's myocardium with cardioplegic fluid.
 3. The method of claim 1wherein the interventional tool is introduced through a cannulapositioned in a percutaneous intercostal penetration.
 4. The method ofclaim 1 wherein the surgical procedure comprises surgically treating aheart valve.
 5. The method of claim 4 further comprising the step ofremoving at least a portion of the heart valve by means of a cuttingtool introduced through a percutaneous intercostal penetration andthrough the internal penetration.
 6. The method of claim 4 furthercomprising the step of introducing a replacement valve through apercutaneous intercostal penetration and through the internalpenetration into the internal cavity.
 7. The method of claim 6 furthercomprising fastening the replacement valve within the internal cavity bymeans of an instrument introduced through a percutaneous intercostalpenetration and through the internal penetration.
 8. The method of claim6 wherein the replacement valve is introduced through a cannulapositioned in a percutaneous intercostal penetration.
 9. The method ofclaim 4 wherein a percutaneous intercostal penetration is created in aright lateral portion of the patient's chest.
 10. The method of claim 9wherein the internal penetration is made in a wall of the patient's leftatrium.
 11. The method of claim 10 wherein the heart valve comprises amitral valve.
 12. The method of claim 10 wherein the heart valvecomprises an aortic valve.
 13. A method of closed-chest replacement of aheart valve in a patient's heart, the method comprising: establishingcardiopulmonary bypass; arresting the patient's heart; viewing thepatient's heart through a scope extending through a percutaneousintercostal penetration in the patient's chest; forming an internalpenetration through a wall of the patient's heart using a cutting toolintroduced through a percutaneous intercostal penetration in thepatient's chest; positioning a replacement valve through a percutaneousintercostal penetration in the patient's chest and through the internalpenetration into a chamber of the heart; and securing the replacementvalve in a valve position in the heart.
 14. The method of claim 13wherein the patient's heart is arrested by occluding the patient's aortabetween the patient's coronary arteries and the patient'sbrachiocephalic artery with an expandable member on a distal end of anendovascular catheter, and perfusing the patient's myocardium withcardioplegic fluid.
 15. The method of claim 13 wherein the heart valvecomprises a mitral valve, the valve position comprising a mitral valveposition.
 16. The method of claim 15 wherein the chamber comprises aleft atrium of the patient's heart.
 17. The method of claim 13 whereinthe percutaneous intercostal penetration is disposed in a right lateralportion of the patient's chest.
 18. The method of claim 13 furthercomprising the step of removing at least a portion of the patient'sheart valve using a cutting tool introduced through a percutaneousintercostal penetration and through the internal penetration.
 19. Themethod of claim 13 further comprising sizing the patient's heart valveby means of a sizing instrument introduced through a percutaneousintercostal penetration and through the internal penetration.
 20. Themethod of claim 13 wherein the replacement valve is positioned by meansof an introducer, the introducer comprising an elongated shaft and meansat a distal end of the shaft for holding the replacement valve.
 21. Themethod of claim 13 wherein the step of fastening comprises suturing thereplacement valve to an annulus at the valve position.
 22. The method ofclaim 21 wherein the step of suturing comprises applying a plurality ofsutures to an annulus at the valve position, drawing the sutures out ofthe patient's body through the internal penetration and through apercutaneous intercostal penetration, and applying the sutures to thereplacement valve.
 23. The method of claim 22 further comprisingradially arranging the sutures in spaced-apart locations about anorganizing ring disposed outside of the patient's body.
 24. The methodof claim 23 further comprising holding the sutures in tension in theorganizing ring as the replacement valve is positioned in the valveposition.
 25. The method of claim 13 wherein the replacement valve isintroduced through a cannula positioned in a percutaneous intercostalpenetration.
 26. A system for closed-chest surgical intervention withina patient's heart or great vessel, the system comprising: means forforming a percutaneous penetration in an intercostal space in thepatient's chest; a visualization scope configured to pass through anintercostal space in the patient's chest for viewing an internal chestcavity; means for arresting the patient's heart from a location outsideof the chest cavity; a cardiopulmonary bypass system, including meansfor delivering oxygenated blood to the patient's arterial system;cutting means positionable through a percutaneous intercostalpenetration into the chest cavity for forming an internal penetration ina wall of the patient's heart or great vessel; and interventional meanspositionable through a percutaneous intercostal penetration and throughthe internal penetration for performing a surgical procedure within theheart or great vessel.
 27. The system of claim 26 wherein the means forarresting the heart comprises an endovascular catheter having expandablemeans for occluding the patient's ascending aorta between the patient'scoronary arteries and the patient's brachiocephalic artery, and aninternal lumen for delivering cardioplegic fluid into the ascendingaorta upstream of the expandable means.
 28. The system of claim 26wherein the interventional means comprises means for securing areplacement valve at a valve location within the patient's heart. 29.The system of claim 28 further comprising a cannula positionable in apercutaneous intercostal penetration, the cannula having a lumen thereinthrough which the replacement valve may be introduced into the internalchest cavity.
 30. The system of claim 28 wherein the replacement valvecomprises an annular portion for attachment to a valve annulus in theheart, the annular portion having an outer diameter, wherein the lumenin the cannula has a cross-sectional height at least equal to the outerdiameter, and a cross-sectional width less than the width of theintercostal space.
 31. The system of claim 28 further comprising cuttingmeans positionable through a percutaneous intercostal penetration andthrough the internal penetration for removing at least a portion of thepatient's heart valve.
 32. The system of claim 28 further comprisingmeans positionable through a percutaneous intercostal penetration andthrough the internal penetration for sizing a valve annulus of thepatient's heart valve.
 33. The system of claim 32 wherein the sizingmeans comprises an elongated shaft and sizing means at a distal end ofthe shaft, wherein the shaft and sizing means may be introduced througha percutaneous intercostal penetration and through the internalpenetration to position the sizing means near the valve annulus.
 34. Thesystem of claim 28 further comprising means for introducing thereplacement valve into the patient's heart, the introducing meanscomprising an elongated shaft having means at a distal end thereof forreleasably holding the replacement valve.
 35. The system of claim 34wherein the introducing means further comprises means actuated from aproximal end of the shaft for pivoting the replacement valve, relativeto the shaft from a first position for introduction through apercutaneous intercostal penetration to a second position for attachmentat the valve location.
 36. The system of claim 28 wherein the means forsecuring the replacement valve comprises means positionable through apercutaneous intercostal penetration for suturing the replacement valveto a valve annulus at the valve location.
 37. The system of claim 36further comprising organizing means for maintaining sutures inspaced-apart positions outside of the chest cavity after the sutureshave been applied to the valve annulus.
 38. The system of claim 37wherein the organizing means is fixed to a proximal end of a cannuladisposed in a percutaneous intercostal penetration, the cannula having alumen through which the replacement valve may be introduced into thechest cavity.
 39. The system of claim 37 further comprising means on theorganizing means for maintaining tension on ends of the sutures tofacilitate advancing the replacement valve along the sutures into thepatient's heart.
 40. The system of claim 26 further comprisingretraction means positionable through an intercostal space in thepatient's chest for opening the internal penetration in the wall of theheart or great vessel.
 41. The system of claim 26 wherein theinterventional means is configured to reach the interior of the heart orgreat vessel from a percutaneous penetration in a right lateral portionof the patient's chest.
 42. The system of claim 41 wherein theinterventional means is at least about 20 cm in length.
 43. Apercutaneous access cannula to facilitate closed-chest replacement of aheart valve in a patient's heart, the access cannula comprising: acannula body configured for placement in an intercostal space in thepatient's chest, the cannula body having a distal end, a proximal end,and a lumen extending therebetween, the lumen being configured to allowpassage of a replacement valve therethrough; and an obturatorpositionable in the lumen, the obturator having a cross-sectional widthless than the width of the intercostal space and a cross-sectionalheight greater than the cross-sectional width.
 44. The access cannula ofclaim 43 wherein the valve prosthesis has an annular attachment portionwith an outer diameter, the obturator having a cross-sectional height atleast equal to the outer diameter.
 45. The access cannula of claim 43wherein the cross-sectional height is about 2 to 6 times thecross-sectional width.
 46. The access cannula of claim 43 wherein theobturator has a generally rectangular cross-section.
 47. The accesscannula of claim 43 wherein the obturator has a generally ovalcross-section.
 48. The access cannula of claim 44 wherein the lumen inthe cannula body has a cross-sectional shape in an unstressed conditionwith a width less than the width of the intercostal space and a heightgreater than the outer diameter of the valve prosthesis.
 49. The accesscannula of claim 48 wherein the lumen has a generally rectangularcross-section.
 50. The access cannula of claim 48 wherein the lumen hasa generally oval-shaped cross-section.
 51. The access cannula of claim48 wherein the cross-sectional height of the lumen is 2 to 6 times thecross-sectional width of the lumen.
 52. The access cannula of claim 43further comprising means at the proximal end of the cannula body forretaining a plurality of sutures extending through the lumen in a spacedapart relationship.
 53. The access cannula of claim 52 wherein thesuture retaining means comprises a plurality of slots in the proximalend of the cannula body in circumferentially spaced positions around thelumen.
 54. The access cannula of claim 52 further comprising means atthe proximal end of the cannula body for maintaining tension on thesutures.
 55. The access cannula of claim 54 wherein the means formaintaining tension comprises an organizing ring having an interiorpassage through which the sutures may extend and a plurality of meanscircumferentially spaced around the passage for frictionally engagingthe sutures.
 56. The access cannula of claim 55 wherein the organizingring comprises an inner ring, an outer ring rotatably coupled to theinner ring, a first plurality of apertures circumferentially spacedabout the inner ring, and a second plurality of aperturescircumferentially spaced about the outer ring, the first and secondplurality of apertures being aligned when the outer ring is in a firstrotational position, and nonaligned when the outer ring is in a secondrotational position.
 57. A cannula system to facilitate surgicalintervention in a patient's body cavity, the cannula system comprising:a cannula body having a distal end, a proximal end, and a lumentherebetween, the lumen being configured for introduction of surgicalinstruments therethrough; and organizer means at the proximal end of thecannula body for retaining a plurality of sutures extending through thelumen from the body cavity in spaced apart positions outside of the bodycavity.
 58. The cannula system of claim 57 wherein the cannula body isconfigured for positioning in an intercostal space in the patient'schest.
 59. The cannula system of claim 57 wherein the organizer meanscomprises a first organizing ring having an interior passage and aplurality of suture retaining means circumferentially spaced about theinterior passage.
 60. The cannula system of claim 59 wherein the firstorganizing ring is fixed to the proximal end of the cannula body withthe interior passage aligned with the lumen.
 61. The cannula system ofclaim 59 wherein the suture retaining means comprise a plurality ofslots in the first organizing ring circumferentially spaced about theinterior passage.
 62. The cannula system of claim 60 further comprisingmeans at the proximal end of the cannula body for maintaining thesutures in tension.
 63. The cannula system of claim 62 wherein the meansfor maintaining the sutures in tension comprises a second organizingring spaced apart from the first organizing ring, the second organizingring having an interior passage and a plurality of meanscircumferentially spaced about the interior passage for holding thesutures in tension.
 64. The cannula system of claim 63 wherein the meansfor holding the sutures in tension comprise slits in the secondorganizing ring for frictionally engaging the sutures.
 65. The cannulasystem of claim 62 wherein the means for maintaining the sutures intension comprises slits in the first organizing ring for frictionallyengaging the sutures.
 66. The cannula system of claim 58 furthercomprising means for holding a replacement valve outside the chest inproximity to the organizer means, whereby a suture extending from thebody cavity through the lumen in the cannula may be applied to thereplacement valve and secured in the organizer means.
 67. The cannulasystem of claim 66 wherein the lumen is configured to facilitateintroduction of the replacement valve therethrough into the body cavity.68. A thoracoscopic device for placement of a replacement valve in avalve position of a patient's heart, the thoracoscopic devicecomprising: an elongated handle having a distal end and a proximal end,the handle configured for positioning through an intercostal space inthe patient's chest, and means at the distal end of the handle forreleasably holding a replacement valve in an orientation forintroduction through the intercostal space.
 69. The thoracoscopic deviceof claim 68 wherein the handle is at least about 20 cm in length. 70.The thoracoscopic device of claim 68 further comprising means forpivoting the replacement valve relative to the handle from a firstorientation for introduction through the intercostal space, to a secondorientation for placement in the valve position.
 71. The thoracoscopicdevice of claim 68 wherein the pivoting means includes an actuatordisposed at the proximal end of the handle.
 72. The thoracoscopic deviceof claim 68 further comprising means at the proximal end of the handlefor releasing the replacement valve from the holding means.
 73. Aprosthesis assembly for closed-chest replacement of a heart valve, theprosthesis assembly comprising: replacement valve having an annularattachment portion and a movable valve portion coupled to the attachmentportion; and holder means releasably mounted to the attachment portion,wherein the holder means is configured to allow introduction of thereplacement valve through an intercostal space in the patient's chest.74. The prosthesis assembly of claim 73 wherein the intercostal spacehas an intercostal width, the replacement valve and holder meanstogether having a profile with a width less than the intercostal width.75. The prosthesis assembly of claim 74 wherein the attachment portionof the replacement valve has an outer diameter which is greater than theintercostal width.
 76. The prosthesis assembly of claim 73 wherein theholder means comprises an elongated handle having a distal end mountedto the replacement valve and a proximal end opposite the distal end, thehandle being configured for introducing the replacement valve into thepatient's heart through the intercostal space.
 77. The prosthesisassembly of claim 76 wherein the handle is at least about 20 cm inlength so as to allow positioning the replacement valve in the heartfrom a right lateral portion of the chest.
 78. The prosthesis assemblyof claim 76 wherein the handle comprises means for releasing thereplacement valve, the releasing means being configured for actuationfrom a proximal end of the handle.
 79. The prosthesis assembly of claim76 wherein the handle comprises means for pivoting the replacement valvefrom a first orientation for introduction through the intercostal spaceto a second orientation for attachment within the patient's heart, thepivoting means being configured for actuation from a proximal end of thehandle.
 80. The prosthesis assembly of claim 73 wherein the intercostalspace is less than about 20 mm in width.
 81. The prosthesis assembly ofclaim 73 wherein the replacement valve and holding means are containedin a sterile pack.